A102658 Numbers which are the sum of two positive cubes and divisible by 31.

217, 341, 1395, 1674, 1736, 2728, 4123, 5425, 5642, 5859, 6293, 7471, 7657, 8029, 8587, 9207, 9269, 9331, 10261, 11160, 11377, 12679, 12896, 13392, 13888, 14167, 14911, 15841, 16120, 17577, 17701, 19747, 20026, 21824, 21979, 24149, 24397

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Mathematica

upto[n_] := Block[{t}, Union@ Reap[ Do[If[Mod[t = x^3 + y^3, 31] == 0, Sow@t], {x, n^(1/3)}, {y, Min[x, (n - x^3)^(1/3)]}]][[2, 1]]]; upto[24500] (* Giovanni Resta, Jun 12 2020 *)

Crossrefs

Cf. A003325, A101421 (divisible by k=7), A101852 (k=11), A094447 (k=13), A099178 (k=17), A102619 (k=19), A101806 (k=23), A224483 (k=29), A102618 (k=37).

Sequence in context: A204765 A289302 A288847 * A145732 A038594 A020232

Adjacent sequences: A102655 A102656 A102657 * A102659 A102660 A102661

Keyword

nonn,easy

Author

Jun Mizuki (suzuki32(AT)sanken.osaka-u.ac.jp), Feb 02 2005

Status

approved