A145320 Numbers n such that there exists x in N : (x+31)^3-x^3=n^2.

6727, 163472827, 3972716635027, 96544959500953327, 2346235601819451117727, 57018217498871341562048227, 1385656719311335740821444894827, 33674229535685863674571412272037527, 818351124790581139708098720213611086327

Offset

1,1

Links

Table of n, a(n) for n=1..9.

Index entries for linear recurrences with constant coefficients, signature (24302,-1).

Formula

a(n+2) = 24302*a(n+1)-a(n).

G.f.: -6727*x*(x-1) / (x^2-24302*x+1). - Colin Barker, Oct 17 2014

Example

a(1)=6727 because the first relation is : (682+31)^3-682^3=6727^2.

Mathematica

LinearRecurrence[{24302, -1}, {6727, 163472827}, 10] (* Paolo Xausa, Jan 17 2024 *)

Prog

(PARI) Vec(-6727*x*(x-1)/(x^2-24302*x+1) + O(x^20)) \\ Colin Barker, Oct 17 2014

Crossrefs

Sequence in context: A237041 A031580 A028543 * A035905 A099778 A049507

Adjacent sequences: A145317 A145318 A145319 * A145321 A145322 A145323

Keyword

nonn,easy

Author

Richard Choulet, Oct 07 2008

Extensions

a(9) from Colin Barker, Oct 17 2014

Status

approved