Ostatnie twierdzenie Fermata mówi, że nie ma pozytywnych, integralnych rozwiązań równania a^n + b^n = c^ndla żadnegon>2 . To udowodnił Andrew Wiles w 1994 roku.

Istnieje jednak wiele „bliskich nieudanych prób”, które prawie spełniają równanie diofantyczne, ale pomijają je o jedno. Dokładnie, wszystkie są większe niż 1 i są integralnymi rozwiązaniami a^3 + b^3 = c^3 + 1(sekwencja jest wartością każdej strony równania, w porządku rosnącym).

Zadanie polega nna wydrukowaniu pierwszych nwartości z tej sekwencji.

Oto kilka pierwszych wartości sekwencji:

1729, 1092728, 3375001, 15438250, 121287376, 401947273, 3680797185, 6352182209, 7856862273, 12422690497, 73244501505, 145697644729, 179406144001, 648787169394, 938601300672, 985966166178, 1594232306569, 2898516861513, 9635042700640, 10119744747001, 31599452533376, 49108313528001, 50194406979073, 57507986235800, 58515008947768, 65753372717929, 71395901759126, 107741456072705, 194890060205353, 206173690790977, 251072400480057, 404682117722064, 498168062719418, 586607471154432, 588522607645609, 639746322022297, 729729243027001

To jest golf golfowy , więc wygrywa najkrótszy kod w bajtach !

Galaretka , 16 bajtów

*3‘
ḊŒc*3S€ċǵ#Ç

Rozwiązanie siłowe. Wypróbuj online!

*3‘           Helper link. Maps r to r³+1.

ḊŒc*3S€ċǵ#Ç  Main link. No arguments.

         µ    Combine the links to the left into a chain.
          #   Read an integer n from STDIN and execute the chain to the left for
              k = 0, 1, 2, ... until n matches were found. Yield the matches.
Ḋ             Dequeue; yield [2, ..., k].
 Œc           Yield all 2-combinations of elements of that range.
   *3         Elevate the integers in each pair to the third power.
     S€       Compute the sum of each pair.
        Ç     Call the helper link, yielding k³+1.
       ċ      Count how many times k³+1 appears in the sums. This yields a truthy 
              (i.e., non-zero) integer if and only if k is a match.
           Ç  Map the helper link over the array of matches.

Brachylog , 31 bajtów

:{#T#>>:{:3^}aLhH,Lb+.-H,#T=,}y

Wypróbuj online!

To nie jest pełna brutalna siła, ponieważ wykorzystuje ograniczenia. Jest to trochę wolne w przypadku TIO (około 20 sekund N = 5). Na mojej maszynie trwa około 5 sekund N = 5i 13 sekund N = 6.

Wyjaśnienie

:{                           }y    Return the first Input outputs of that predicate
  #T                               #T is a built-in list of 3 variables
    #>                             #T must contain strictly positive values
      >                            #T must be a strictly decreasing list of integers
       :{:3^}aL                    L is the list of cubes of the integers in #T
              LhH,                 H is the first element of L (the biggest)
                  Lb+.             Output is the sum of the last two elements of L
                     .-H,          Output - 1 = H
                         #T=,      Find values for #T that satisfy those constaints

Perl, 78 bajtów

#!perl -nl
grep$_<(($_+2)**(1/3)|0)**3,map$i**3-$_**3,2..$i++and$_-=print$i**3+1while$_

Podejście brutalnej siły. Couting shebang jako dwa, dane wejściowe są pobierane ze standardowego wejścia.

Przykładowe użycie

$ echo 10 | perl fermat-near-miss.pl
1729
1092728
3375001
15438250
121287376
401947273
3680797185
6352182209
7856862273
12422690497

Wypróbuj online!

Mathematica, 95 bytes

(b=9;While[Length[a=Select[Union@@Array[#^3+#2^3&,{b,b},2],IntegerQ[(#-1)^3^-1]&,#]]<#,b++];a)&

Unnamed function taking a single positive integer argument # and returning a list of the desired # integers. Spaced for human readability:

1  (b = 9; While[
2    Length[ a =
3      Select[
4        Union @@ Array[#^3 + #2^3 &, {b, b}, 2],
5        IntegerQ[(# - 1)^3^-1] &
6      , #]
7    ] < #, b++
8  ]; a) &

Line 4 calculates all possible sums of cubes of integers between 2 and b+1 (with the initialization b=9 in line 1) in sorted order. Lines 3-5 select from those sums only those that are also one more than a perfect cube; line 6 limits that list to at most # values, which are stored in a. But if this list has in fact fewer than # values, the While loop in lines 1-7 increments b and tries again. Finally, line 8 outputs a once it's the right length.

Holy hell this version is slow! For one extra byte, we can change b++ in line 7 to b*=9 and make the code actually run in reasonable time (indeed, that's how I tested it).

Racket 166 bytes

(let((c 0)(g(λ(x)(* x x x))))(for*((i(in-naturals))(j(range 1 i))(k(range j i))#:final(= c n))
(when(=(+(g j)(g k))(+ 1(g i)))(displayln(+ 1(g i)))(set! c(+ 1 c)))))

Ungolfed:

(define (f n)
  (let ((c 0)
        (g (λ (x) (* x x x))))
    (for* ((i (in-naturals))
           (j (range 1 i))
           (k (range j i))
           #:final (= c n))
      (when (= (+ (g j) (g k))
               (+ 1 (g i)))
        (displayln (+ 1(g i)))
        (set! c (add1 c))))))

Testing:

(f 5)

Output:

1729
1092728
3375001
15438250
121287376

Python 2, 102 98 bytes

def f(n,c=2):z=c**3+1;t=z in[(k/c)**3+(k%c)**3for k in range(c*c)];return[z]*n and[z]*t+f(n-t,c+1)

Try it online!

Pari/GP, 107 bytes

F(n)=c=2;while(n>0,c++;C=c^3+1;a=2;b=c-1;while(a<b,K=a^3+b^3;if(K==C,print(C);n--;break);if(K>C, b--,a++)))

Finds the first 10 solutions in 10 sec.

Goal: a^3+b^3 = c^3+1

1. Gets number of required solutions by function-argument n

2. Increases c from 3 and for each c^3+1 searches a and b with 1 < a <= b < c such that a^3+b^3=c^3+1 . If found, decrease required number of further soulutions n by 1 and repeat

3. Finishes, when number of furtherly required solutions (in n) equals 0

Call it to get the first ten solutions:

F(10)

Readable code (requires leading and trailing braces as indicators for block-notation of the function. Also for convenience prints all variables of a solution):

{F(m) = c=2;
   while(m>0,        
     c++;C=c^3+1;             
     a=2;b=c-1;                
     while(a<b,                
           K=a^3+b^3;               
            if(K==C,print([a,b,c,C]);m--;break);
            if(K>C, b--,a++);
          );
    );}

Pari/GP, 93 bytes

(Improvement by Dennis)

F(n)=c=2;while(n,C=c^3+1;a=2;b=c++;while(a<b,if(K=a^3+b^3-C,b-=K>0;a+=K<0,print(C);n--;b=a)))              

Python 2, 122 119 Bytes

^{why are you still upvoting? Dennis crushed this answer ;)}

Welcome to the longest solution to this question :/ I managed to shave off a whole byte by making longer conditions and removing as much indentation as possible.

x,y,z=2,3,4
n=input()
while n:
 if y**3+x**3-z**3==1and x<y<z:print z**3+1;n-=1
 x+=1
 if y<x:y+=1;x=2
 if z<y:z+=1;y=3

Output for n = 5:

1729
1092728
3375001
15438250
121287376

TI-Basic, 90 bytes

There must be a shorter way...

Prompt N
2->X
3->Y
4->Z
While N
If 1=X³+Y³-Z³ and X<Y and Y<Z
Then
DS<(N,0
X+1->X
If Y<X
Then
2->X
Y+1->Y
End
If Z<Y
Then
3->Y
Z+1->Z
End
End

MATLAB, 94 bytes

Another brute-force solution:

for z=4:inf,for y=3:z,for x=2:y,c=z^3+1;if x^3+y^3==c,n=n-1;c,if~n,return,end,end,end,end,end

Output for n=4:

>> n=4; fermat_near_misses    
c =
        1729
c =
     1092728
c =
     3375001
c =
    15438250

Suppressing the c= part of the display increases the code to 100 bytes

for z=4:inf,for y=3:z,for x=2:y,c=z^3+1;if x^3+y^3==c,n=n-1;disp(c),if~n,return,end,end,end,end,end

>> n=4; fermat_near_misses_cleandisp    
        1729
     1092728
     3375001
    15438250

C#, 188 174 187 136 bytes

Golfed version thanks to TheLethalCoder for his great code golfing and tips (Try online!):

n=>{for(long a,b,c=3;n>0;c++)for(a=2;a<c;a++)for(b=a;b<c;b++)if(a*a*a+b‌​*b*b==c*c*c+1)System‌​.Console.WriteLin‌e(‌​c*c*(a=c)+n/n--);};

Execution time to find the first 10 numbers: 33,370842 seconds on my i7 laptop (original version below was 9,618127 seconds for the same task).

Ungolfed version:

using System;

public class Program
{
    public static void Main()
    {
        Action<int> action = n =>
        {
            for (long a, b, d, c = 3; n > 0; c++)
                for (a = 2; a < c; a++)
                    for (b = a; b < c; b++)
                        if (a * a * a + b‌ * b * b == c * c * c + 1)
                            System‌.Console.WriteLin‌e( c * c * (a = c) + n / n--);
        };

        //Called like
        action(5);
    }
}

Previous golfed 187 bytes version including using System;

using System;static void Main(){for(long a,b,c=3,n=int.Parse(Console.ReadLine());n>0;c++)for(a=2;a<c;a++)for(b=a;b<c;b++)if(a*a*a+b*b*b==c*c*c+1)Console.WriteLin‌​e(c*c*(a=c)+n/n--);}

Previous golfed 174 bytes version (thanks to Peter Taylor):

static void Main(){for(long a,b,c=3,n=int.Parse(Console.ReadLine());n>0;c++)for(a=2;a<c;a++)for(b=a;b<c;b++)if(a*a*a+b*b*b==c*c*c+1)Console.WriteLin‌​e(c*c*(a=c)+n/n--);}

Previous (original) golfed 188 bytes version (Try online!):

static void Main(){double a,b,c,d;int t=0,n=Convert.ToInt32(Console.ReadLine());for(c=3;t<n;c++)for(a=2;a<c;a++)for(b=a;b<c;b++){d=(c*c*c)+1;if(a*a*a+b*b*b==d){Console.WriteLine(d);t++;}}}

Execution time to find the first 10 numbers: 9,618127 seconds on my i7 laptop.

This is my first ever attempt in C# coding... A bit verbose compared to other languages...

GameMaker Language, 119 bytes

Why is show_message() so long :(

x=2y=3z=4w=argument0 while n>0{if x*x*x+y*y*y-z*z*z=1&x<y&y<z{show_message(z*z*z+1)n--}x++if y<x{x=2y++}if z<y{y=3z++}}

x,y,z=2,3,4 n=input() while n: if y3+x3-z3==1and x3+1;n-=1 x+=1 if y

Axiom, 246 bytes

h(x:PI):List INT==(r:List INT:=[];i:=0;a:=1;repeat(a:=a+1;b:=1;t:=a^3;repeat(b:=b+1;b>=a=>break;q:=t+b^3;l:=gcd(q-1,223092870);l~=1 and(q-1)rem(l^3)~=0=>0;c:=round((q-1)^(1./3))::INT;if c^3=q-1 then(r:=cons(q,r);i:=i+1;i>=x=>return reverse(r)))))

ungof and result

-- hh returns x in 1.. numbers in a INT list [y_1,...y_x] such that 
-- for every y_k exist a,b,c in N with y_k=a^3+b^3=c^3+1 
hh(x:PI):List INT==
   r:List INT:=[]
   i:=0;a:=1
   repeat
      a:=a+1
      b:=1
      t:=a^3
      repeat
          b:=b+1
          b>=a=>break
          q:=t+b^3
          l:=gcd(q-1,223092870);l~=1 and (q-1)rem(l^3)~=0 =>0 -- if l|(q-1)=> l^3|(q-1)
          c:=round((q-1.)^(1./3.))::INT
          if c^3=q-1 then(r:=cons(q,r);i:=i+1;output[i,a,b,c];i>=x=>return reverse(r))

(3) -> h 12
   (3)
   [1729, 1092728, 3375001, 15438250, 121287376, 401947273, 3680797185,
    6352182209, 7856862273, 12422690497, 73244501505, 145697644729]
                                                       Type: List Integer