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A014439 Differences between two positive cubes in exactly 1 way. 7
7, 19, 26, 37, 56, 61, 63, 91, 98, 117, 124, 127, 152, 169, 189, 208, 215, 217, 218, 271, 279, 296, 316, 331, 335, 342, 386, 387, 397, 448, 469, 485, 488, 504, 511, 513, 547, 602, 604, 631, 657, 665, 702, 784, 817, 819, 866, 875, 919, 936, 973, 988, 992 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

N:= 1000: # to get all terms <= N

X:= floor(sqrt(N/3)):

V:= Vector(N):

for x from 2 to X do

  if x^3 > N then

     y0:= iroot(x^3-N, 3);

     if x^3 - y0^3 > N then y0:= y0+1 fi;

  else y0:= 1 fi;

  for y from y0 to x-1 do

     V[x^3 - y^3] := V[x^3 - y^3]+1

  od

od: select(t -> V[t] = 1, [$1..N]); # Robert Israel, Dec 11 2015

MATHEMATICA

r = 992; p = 3; Sort@Drop[Flatten@Select[Tally@Reap[Do[n = i^p - j^p; If[n <= r, Sow[n]], {i, Ceiling[(r/p)^(1/(p - 1))]}, {j, i}]][[2, 1]], #[[2]] == 1 &], {2, -1, 2}] (* Arkadiusz Wesolowski, Dec 10 2015 *)

CROSSREFS

Cf. A000578, A038593, A181123, A034179 (more than one way), A014440 (exactly two ways), A265625 (more than two ways), A014441 (exactly three ways).

Sequence in context: A006063 A181123 A038593 * A175376 A175366 A117609

Adjacent sequences:  A014436 A014437 A014438 * A014440 A014441 A014442

KEYWORD

nonn

AUTHOR

Glen Burch (gburch(AT)erols.com)

EXTENSIONS

Corrected and extended by Don Reble, Nov 19 2006

STATUS

approved

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Last modified October 22 09:56 EDT 2019. Contains 328315 sequences. (Running on oeis4.)