A259403 Pentagonal numbers (A000326) that are the sum of eleven consecutive pentagonal numbers.

2882, 27676, 1114135, 10982301, 443390277, 4370895551, 176468183540, 1739605414426, 70233893626072, 692358584013426, 27952913194960545, 275556976831896551, 11125189217700638267, 109670984420510781301, 4427797355731659037150, 43648776242386459028676

Offset: 1

Author

Colin Barker, Jun 26 2015

Keywords

• nonn
• easy

Examples

			2882 is in the sequence because P(44) = 2882 = 92 + 117 + 145 + 176 + 210 + 247 + 287 + 330 + 376 + 425 + 477 = P(8)+ ... +P(18).
		

Links

• Colin Barker, Table of n, a(n) for n = 1..767
• Index entries for linear recurrences with constant coefficients, signature (1,398,-398,-1,1).

Crossrefs

Cf. A000326, A133301, A257714, A257715, A259402, A259404.

Programs

Mathematica

LinearRecurrence[{1,398,-398,-1,1},{2882,27676,1114135,10982301,443390277},30] (* Harvey P. Dale, Jan 21 2017 *)

PARI

Vec(-11*x*(16*x^4+14*x^3-5507*x^2+2254*x+262)/((x-1)*(x^2-20*x+1)*(x^2+20*x+1)) + O(x^20))

Formula

G.f.: -11*x*(16*x^4+14*x^3-5507*x^2+2254*x+262) / ((x-1)*(x^2-20*x+1)*(x^2+20*x+1)).