A038847 Odd numbers that are differences between two positive cubes.

7, 19, 37, 61, 63, 91, 117, 127, 169, 189, 215, 217, 271, 279, 331, 335, 387, 397, 469, 485, 511, 513, 547, 631, 657, 665, 721, 817, 819, 875, 919, 973, 999, 1027, 1115, 1141, 1197, 1261, 1267, 1323, 1385, 1387, 1413, 1519, 1603, 1647, 1657, 1685, 1701

Offset: 1

Author

Jeff Burch

Keywords

• nonn

Links

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

Crossrefs

Cf. A038848.

Odd terms of A181123.

Programs

Maple

N:= 2000: # to get all terms <= N
S:= {}:
for x from 1 to floor(1/2 + sqrt(12*N-3)/6) do
  S:= S union {seq(x^3-y^3, y= x-1..max(1,ceil(surd(x^3-N,3))),-2)}
od:
sort(convert(S,list)); # Robert Israel, Jan 21 2019

Mathematica

With[{nn=50},Take[Select[Union[Abs[#[[2]]-#[[1]]]&/@Subsets[Range[nn]^3,{2}]],OddQ],nn]] (* Harvey P. Dale, Jan 18 2013 *)

Extensions

Definition corrected by Robert Israel, Jan 21 2019