A022284 a(n) = n*(27*n - 1)/2.

0, 13, 53, 120, 214, 335, 483, 658, 860, 1089, 1345, 1628, 1938, 2275, 2639, 3030, 3448, 3893, 4365, 4864, 5390, 5943, 6523, 7130, 7764, 8425, 9113, 9828, 10570, 11339, 12135, 12958, 13808, 14685, 15589

Offset: 0

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 0..5000
• Index entries for linear recurrences with constant coefficients, signature (3,-3,1).

Crossrefs

Cf. A000217, A022285.

Cf. similar sequences listed in A022288.

Programs

Mathematica

Table[n (27 n - 1)/2, {n, 0, 40}] (* Bruno Berselli, Oct 14 2016 *)
LinearRecurrence[{3,-3,1},{0,13,53},40] (* Harvey P. Dale, Jul 04 2022 *)

PARI

a(n)=n*(27*n-1)/2 \\ Charles R Greathouse IV, Jun 17 2017

Formula

a(n) = a(n-1) + 27*n - 14 for n>0, a(0)=0. - Vincenzo Librandi, Aug 04 2010

G.f.: x*(13 + 14*x)/(1 - x)^3 . - R. J. Mathar, Aug 04 2016

a(n) = A000217(14*n-1) - A000217(13*n-1). - Bruno Berselli, Oct 14 2016

E.g.f.: (x/2)*(27*x + 26)*exp(x). - G. C. Greubel, Aug 23 2017