Os números de táxi ou OEIS A011541 são os menos números que podem ser representados como n somas diferentes de dois números inteiros positivos em cubos, para n sucessivos .

Você precisará imprimir o número do n º táxi. Isso deve funcionar para qualquer n em teoria.

No entanto, como apenas 6 números de táxis foram descobertos até agora, não haverá n acima de 6. Os números são 2, 1729, 87539319, 6963472309248, 48988659276962496, 24153319581254312065344.

Você não pode codificar essas variáveis ​​porque seu programa deve funcionar para qualquer n arbitrário em teoria.

Haskell, 60 bytes

f n=[k|k<-[0..],n<=sum[1|x<-[1..k],y<-[1..x],x^3+y^3==k]]!!0

Bem direto. Conta quantas maneiras um número kpode ser escrito como uma soma de dois cubos. Filtra para ké de tal forma que esse número seja pelo menos ne pega o primeiro.

Um método de comprimento igual com until:

f n=until(\k->n<=sum[1|x<-[1..k],y<-[1..x],x^3+y^3==k])(+1)0

Táxi, 4758 bytes

Qual idioma melhor para calcular os números de táxis do que aquele que simula táxis?
_{Isso é uma piada. Existem tantos idiomas melhores. O que aconteceu nos últimos dois dias da minha vida?}

Go to Post Office:w 1 l 1 r 1 l.Pickup a passenger going to The Babelfishery.Go to The Babelfishery:s 1 l 1 r.Pickup a passenger going to Cyclone.Go to Cyclone:n 1 l 1 l 2 r.Pickup a passenger going to Bird's Bench.Pickup a passenger going to Cyclone.Go to Zoom Zoom:n.Go to Cyclone:w.Pickup a passenger going to Rob's Rest.Pickup a passenger going to Cyclone.Go to Bird's Bench:n 1 r 2 r 1 l.Go to Rob's Rest:n.Go to Cyclone:s 1 l 1 l 2 l.[a]Pickup a passenger going to Firemouth Grill.Pickup a passenger going to The Underground.Go to Zoom Zoom:n.Go to Firemouth Grill:w 3 l 2 l 1 r.Go to The Underground:e 1 l.Switch to plan "b" if no one is waiting.Pickup a passenger going to Cyclone.Go to Cyclone:n 3 l 2 l.Switch to plan "a".[b]Go to Firemouth Grill:s 1 r.[c]Pickup a passenger going to Cyclone.Go to Cyclone:w 1 l 1 r 2 r.Pickup a passenger going to Cyclone.Go to Zoom Zoom:n.Go to Cyclone:w.Pickup a passenger going to Multiplication Station.Pickup a passenger going to Multiplication Station.Pickup a passenger going to Multiplication Station.Go to Multiplication Station:s 1 l 2 r 4 l.Pickup a passenger going to Trunkers.Go to Trunkers:s 1 r 2 l.Go to Firemouth Grill:e 1 l 1 r.Switch to plan "e" if no one is waiting.Switch to plan "c".[e]Go to Trunkers:w 1 l 1 r.Pickup a passenger going to Cyclone.Go to Cyclone:w 2 r.Pickup a passenger going to Sunny Skies Park.Go to Sunny Skies Park:n 1 r.[f]Go to Trunkers:s 1 l.Switch to plan "g" if no one is waiting.Pickup a passenger going to Sunny Skies Park.Go to Cyclone:w 2 r.Pickup a passenger going to Cyclone.Go to Zoom Zoom:n.Go to Cyclone:w.Go to Sunny Skies Park:n 1 r.Switch to plan "f".[g]Go to Cyclone:w 2 r.Switch to plan "h" if no one is waiting.Pickup a passenger going to Firemouth Grill.Go to Zoom Zoom:n.Go to Firemouth Grill:w 3 l 2 l 1 r.Go to Trunkers:w 1 l 1 r.Switch to plan "g".[h]Go to Sunny Skies Park:n 1 r.Switch to plan "i" if no one is waiting.Pickup a passenger going to Cyclone.Go to Firemouth Grill:s 1 l 1 l 1 r.Pickup a passenger going to Addition Alley.Go to Cyclone:w 1 l 1 r 2 r.Pickup a passenger going to Addition Alley.Pickup a passenger going to Trunkers.Go to Zoom Zoom:n.Go to Trunkers:w 3 l.Go to Addition Alley:w 2 r 2 r 1 r.Pickup a passenger going to Narrow Path Park.Go to Narrow Path Park:n 1 r 1 l 1 r.Go to Cyclone:w 1 l 1 r 2 l.Switch to plan "h".[i]Go to Trunkers:s 1 l.Pickup a passenger going to Knots Landing.Go to Knots Landing:e 1 r 2 l 5 r.Go to Trunkers:w 1 l 3 r 1 l.Switch to plan "j" if no one is waiting.Go to Firemouth Grill:e 1 l 1 r.Switch to plan "e".[j]0 is waiting at Starchild Numerology.Go to Starchild Numerology:w 1 l 2 l.Pickup a passenger going to Addition Alley.[k]Go to Rob's Rest:w 1 r 2 l 1 r.Pickup a passenger going to Cyclone.Go to Cyclone:s 1 l 1 l 2 l.Pickup a passenger going to Rob's Rest.Pickup a passenger going to Equal's Corner.Go to Zoom Zoom:n.Go to Rob's Rest:w 2 l 2 r 1 r.Go to Narrow Path Park:s 1 l 1 l 1 r 1 r 2 l 5 l.Switch to plan "o" if no one is waiting.Pickup a passenger going to Equal's Corner.Go to Equal's Corner:w 1 l 1 r 2 l 1 l.Switch to plan "l" if no one is waiting.Pickup a passenger going to Knots Landing.1 is waiting at Starchild Numerology.Switch to plan "m".[l]0 is waiting at Starchild Numerology.[m]Go to Starchild Numerology:n 1 r.Pickup a passenger going to Addition Alley.Go to Addition Alley:w 1 r 3 r 1 r 1 r.Pickup a passenger going to Addition Alley.Go to Knots Landing:n 1 r 2 r 1 l.Go to Starchild Numerology:w 1 l 3 r 1 l 1 l 2 l.Switch to plan "k".[o]0 is waiting at Starchild Numerology.Go to Starchild Numerology:w 1 l 1 r 2 l 1 l 3 l.Pickup a passenger going to Equal's Corner.Go to Equal's Corner:w 1 l.Go to Addition Alley:n 4 r 1 r 1 r.Pickup a passenger going to Equal's Corner.Go to Bird's Bench:n 1 l 1 l 1 l 2 r 1 l.Pickup a passenger going to Cyclone.Go to Cyclone:n 1 r 1 l 2 l.Pickup a passenger going to Bird's Bench.Pickup a passenger going to Equal's Corner.Go to Bird's Bench:n 1 r 2 r 1 l.Go to Equal's Corner:n 1 r 1 r.Switch to plan "p" if no one is waiting.Go to Starchild Numerology:n 1 r.Go to Rob's Rest:w 1 r 2 l 1 r.Pickup a passenger going to The Babelfishery.Go to The Babelfishery:s 1 l 1 l 1 r 1 r 1 r.Pickup a passenger going to Post Office.Go to Post Office:n 1 l 1 r.Switch to plan "z".[p]1 is waiting at Starchild Numerology.Go to Starchild Numerology:n 1 r.Pickup a passenger going to Addition Alley.Go to Rob's Rest:w 1 r 2 l 1 r.Pickup a passenger going to Addition Alley.Go to Addition Alley:s 1 l 1 l 2 r 1 r 1 r.Pickup a passenger going to Cyclone.Go to Cyclone:n 1 l 1 l.Pickup a passenger going to Rob's Rest.Pickup a passenger going to Cyclone.Go to Rob's Rest:n 1 r 2 r 1 r.Go to Cyclone:s 1 l 1 l 2 l.Switch to plan "a".[z]

Experimente online!
Experimente online, mas com comentários e quebras de linha!
_{Nota: O TIO pode manipular uma entrada 1mas 2acima e causar um problema de tempo limite. Escrevi um pequeno trecho para imprimir o valor que está sendo verificado a cada iteração, e isso só ocorreu 137antes do tempo limite. Se alguém que sabe o que está fazendo pode executá-lo através de um intérprete (a página inicial possui links para uma versão em C ++ ) para verificar valores mais altos, eu agradeceria. Pode levar muito tempo para ser executado.}

Ungolfed com comentários:

[ FIND THE NTH TAXI CAB NUMBER ]
[ https://en.wikipedia.org/wiki/Taxicab_number ]
[ Inspired by https://codegolf.stackexchange.com/q/73827/38183 ]

[ A taxi cab number T(n) is the smallest number that can be made from the sum  ]
[ of two positive cubes in n different ways. For example, T(1) = 2 because     ]
[ 2 = 1^3 + 1^3. That is the only way to make 2 by summing positive cubes. No  ]
[ solution exists for 1 so 2 is T(1). T(2) = 1729 = 1^3 + 12^3 = 9^3 + 10^3.   ]
[ This program takes n as input and finds T(n). The (bad) psuedocode is:       ]
[                                                                              ]
[    S = STDIN;  // Use Bird's Bench                                           ]
[    T = STDIN;  // Use Rob's Rest. Saves bytes and T(n) > n is always true.   ]
[    while (true) {                                                            ]
[       // Fill an array (Firemouth Grill) with the numbers 1 through T        ]
[       // This will make it much easier to compute the cubes because a taxi   ]
[       // can only carry three passengers at a time.                          ]
[       for (i = T; i > 0; i--) { A.push(i) }                                  ]
[       // Fill an array (Trunkers) with the cubes of all integers 1 through T ]
[       for (i = T; i > 0; i--) { B.push(i ^ 3) }                              ]
[       // Fill an array (Sunny Skies Park) with each possible sum of cubes    ]
[       while (B(0) != null) {                                                 ]
[          // Make copies of the next value to add to each remaining value     ]
[          C.push(B(0));                                                       ]
[          while (B(0) != null) {                                              ]
[             C.push(C(0));                                                    ]
[             D.push(B(0));                                                    ]
[             B.shift();                                                       ]
[          }                                                                   ]
[          // Store each possible sum with this cube                           ]
[          while (C(0) != null) {                                              ]
[             E.push(C(0) + D(0));                                             ]
[             B.push(D(0));                                                    ]
[             C.shift;                                                         ]
[             D.shift;                                                         ]
[          }                                                                   ]
[       }                                                                      ]
[       // Check each possible sum to see if it equals T                       ]
[       N = 0;                                                                 ]
[       while (D(0) != null) {                                                 ]
[          if (D(0) = T) { N++ }                                               ]
[          D.shift();                                                          ]
[       }                                                                      ]
[       // If we found the desired number of sums, ouput and break             ]
[       // Otherwise, go to the next T and keep going                          ]
[       if (N = S) {                                                           ]
[          print(T);                                                           ]
[          break;                                                              ]
[       } else {                                                               ]
[          T++;                                                                ]
[       }                                                                      ]
[    }                                                                         ]
[                                                                              ]



[ S = STDIN;  // Use Bird's Bench                                         ]
[ T = STDIN;  // Use Rob's Rest. Saves bytes and T(n) > n is always true. ]
Go to Post Office: west 1st left 1st right 1st left.
Pickup a passenger going to The Babelfishery.
Go to The Babelfishery: south 1st left 1st right.
Pickup a passenger going to Cyclone.
Go to Cyclone: north 1st left 1st left 2nd right.
Pickup a passenger going to Bird's Bench.
Pickup a passenger going to Cyclone.
Go to Zoom Zoom: north.
Go to Cyclone: west.
Pickup a passenger going to Rob's Rest.
Pickup a passenger going to Cyclone.
Go to Bird's Bench: north 1st right 2nd right 1st left.
Go to Rob's Rest: north.


[ // Fill an array (Firemouth Grill) with the numbers 1 through T      ]
[ // This will make it much easier to compute the cubes because a taxi ]
[ //  can only carry three passengers at a time.                       ]
[ for (i = T; i > 0; i--) { A.push(i) }                                ]
Go to Cyclone: south 1st left 1st left 2nd left.
[a]
Pickup a passenger going to Firemouth Grill.
Pickup a passenger going to The Underground.
Go to Zoom Zoom: north.
Go to Firemouth Grill: west 3rd left 2nd left 1st right.
Go to The Underground: east 1st left.
Switch to plan "b" if no one is waiting.
Pickup a passenger going to Cyclone.
Go to Cyclone: north 3rd left 2nd left.
Switch to plan "a".


[b]
[ // Fill an array (Trunkers) with the cubes of all integers 1 through T ]
[ for (i = T; i > 0; i--) { B.push(i ^ 3); }                             ]
Go to Firemouth Grill: south 1st right.
[c]
Pickup a passenger going to Cyclone.
Go to Cyclone: west 1st left 1st right 2nd right.
Pickup a passenger going to Cyclone.
Go to Zoom Zoom: north.
Go to Cyclone: west.
Pickup a passenger going to Multiplication Station.
Pickup a passenger going to Multiplication Station.
Pickup a passenger going to Multiplication Station.
Go to Multiplication Station: south 1st left 2nd right 4th left.
Pickup a passenger going to Trunkers.
Go to Trunkers: south 1st right 2nd left.
Go to Firemouth Grill: east 1st left 1st right.
Switch to plan "e" if no one is waiting.
Switch to plan "c".


[e]
[ // Fill an array with each possible sum of cubes                ]
[ while (B(0) != null) {                                          ]
[ // Make copies of the next value to add to each remaining value ]
[ C.push(B(0));                                                   ]
[ while (B(0) != null) {                                          ]
[    C.push(C(0));                                                ]
[    D.push(B(0));                                                ]
[    B.shift();                                                   ]
[ }                                                               ]
[ Setup Cyclone with a copy of the first value ]
Go to Trunkers: west 1st left 1st right.
Pickup a passenger going to Cyclone.
Go to Cyclone: west 2nd right.
Pickup a passenger going to Sunny Skies Park.
Go to Sunny Skies Park: north 1st right.

[f]
[ Move any remaining values to Sunny Skies Park, duplicating Cyclone each time ]
Go to Trunkers: south 1st left.
Switch to plan "g" if no one is waiting.
Pickup a passenger going to Sunny Skies Park.
Go to Cyclone: west 2nd right.
Pickup a passenger going to Cyclone.
Go to Zoom Zoom: north.
Go to Cyclone: west.
Go to Sunny Skies Park: north 1st right.
Switch to plan "f".

[g]
[ // Store each possible sum with this cube ]
[ while (C(0) != null) {                    ]
[    E.push(C(0) + D(0));                   ]
[    B.push(D(0));                          ]
[    C.shift;                               ]
[    D.shift;                               ]
[ }                                         ]
[ Move everything at Cyclone to Firemouth Grill ]
Go to Cyclone: west 2nd right.
Switch to plan "h" if no one is waiting.
Pickup a passenger going to Firemouth Grill.
Go to Zoom Zoom: north.
Go to Firemouth Grill: west 3rd left 2nd left 1st right.
Go to Trunkers: west 1st left 1st right.
Switch to plan "g".

[h]
[ Copy Sunny Skies Park to Trunkers and add it to Firemouth Grill ]
Go to Sunny Skies Park: north 1st right.
Switch to plan "i" if no one is waiting.
Pickup a passenger going to Cyclone.
Go to Firemouth Grill: south 1st left 1st left 1st right.
Pickup a passenger going to Addition Alley.
Go to Cyclone: west 1st left 1st right 2nd right.
Pickup a passenger going to Addition Alley.
Pickup a passenger going to Trunkers.
Go to Zoom Zoom: north.
Go to Trunkers: west 3rd left.
Go to Addition Alley: west 2nd right 2nd right 1st right.
Pickup a passenger going to Narrow Path Park.
Go to Narrow Path Park: north 1st right 1st left 1st right.
Go to Cyclone: west 1st left 1st right 2nd left.
Switch to plan "h".

[i]
[ } // End of 'while (B(0) != null)' up near plan "e" ]
Go to Trunkers: south 1st left.
Pickup a passenger going to Knots Landing.
Go to Knots Landing: east 1st right 2nd left 5th right.
Go to Trunkers: west 1st left 3rd right 1st left.
Switch to plan "j" if no one is waiting.
Go to Firemouth Grill: east 1st left 1st right.
Switch to plan "e".


[j]
[ // Check each possible sum to see if it equals T ]
[ N = 0;                                           ]
[ while (D(0) != null) {                           ]
[    if (D(0) = T) { N++; }                        ]
[    D.shift();                                    ]
[ }                                                ]
[ Set N = 0 ]
0 is waiting at Starchild Numerology.
Go to Starchild Numerology: west 1st left 2nd left.
Pickup a passenger going to Addition Alley.

[k]
[ Pickup T ]
Go to Rob's Rest: west 1st right 2nd left 1st right.
Pickup a passenger going to Cyclone.
Go to Cyclone: south 1st left 1st left 2nd left.
Pickup a passenger going to Rob's Rest.
Pickup a passenger going to Equal's Corner.
Go to Zoom Zoom: north.
Go to Rob's Rest: west 2nd left 2nd right 1st right.
Go to Narrow Path Park: south 1st left 1st left 1st right 1st right 2nd left 5th left.
Switch to plan "o" if no one is waiting.

[ Check the next value against T ]
Pickup a passenger going to Equal's Corner.
Go to Equal's Corner: west 1st left 1st right 2nd left 1st left.
Switch to plan "l" if no one is waiting.

[ It's a match so N = N + 1 ]
Pickup a passenger going to Knots Landing.
1 is waiting at Starchild Numerology.
Switch to plan "m".

[l]
[ It's not a match so N = N + 0 ]
0 is waiting at Starchild Numerology.

[m]
Go to Starchild Numerology: north 1st right.
Pickup a passenger going to Addition Alley.
Go to Addition Alley: west 1st right 3rd right 1st right 1st right.
Pickup a passenger going to Addition Alley.
Go to Knots Landing: north 1st right 2nd right 1st left.
Go to Starchild Numerology: west 1st left 3rd right 1st left 1st left 2nd left.
Switch to plan "k".


[o]
[ // If we found the desired number of sums, ouput and break ]
[ // Otherwise, go to the next T and keep going              ]
[ if (N = S) {                                               ]
[    print(T);                                               ]
[    break;                                                  ]
[ } else {                                                   ]
[    T++;                                                    ]
[ }                                                          ]
[ T is still going to Equal's Corner so just get rid of it ]
0 is waiting at Starchild Numerology.
Go to Starchild Numerology: west 1st left 1st right 2nd left 1st left 3rd left.
Pickup a passenger going to Equal's Corner.
Go to Equal's Corner: west 1st left.

[ N is still going to Addition Alley so redirect it to Equal's Corner ]
Go to Addition Alley: north 4th right 1st right 1st right.
Pickup a passenger going to Equal's Corner.

[ Compare N = S ]
Go to Bird's Bench: north 1st left 1st left 1st left 2nd right 1st left.
Pickup a passenger going to Cyclone.
Go to Cyclone: north 1st right 1st left 2nd left.
Pickup a passenger going to Bird's Bench.
Pickup a passenger going to Equal's Corner.
Go to Bird's Bench: north 1st right 2nd right 1st left.
Go to Equal's Corner: north 1st right 1st right.
Switch to plan "p" if no one is waiting.

[ It's a match! The value we want is T, waiting at Rob's Rest. ]
[Go to Rob's Rest:n 3 l 1 r.]
Go to Starchild Numerology: north 1st right.
Go to Rob's Rest: west 1st right 2nd left 1st right.
Pickup a passenger going to The Babelfishery.
Go to The Babelfishery: south 1st left 1st left 1st right 1st right 1st right.
Pickup a passenger going to Post Office.
Go to Post Office: north 1st left 1st right.
Switch to plan "z".

[p]
[ It's not a match. T = T + 1 and start over. ]
1 is waiting at Starchild Numerology.
Go to Starchild Numerology: north 1st right.
Pickup a passenger going to Addition Alley.
Go to Rob's Rest: west 1st right 2nd left 1st right.
Pickup a passenger going to Addition Alley.
Go to Addition Alley: south 1st left 1st left 2nd right 1st right 1st right.
Pickup a passenger going to Cyclone.
Go to Cyclone: north 1st left 1st left.
Pickup a passenger going to Rob's Rest.
Pickup a passenger going to Cyclone.
Go to Rob's Rest: north 1st right 2nd right 1st right.
Go to Cyclone: south 1st left 1st left 2nd left.
Switch to plan "a".

[z]
[ Terminate program with 10 less bytes than going back to the Taxi Garage ]