A022279 a(n) = n*(21*n + 1)/2.

0, 11, 43, 96, 170, 265, 381, 518, 676, 855, 1055, 1276, 1518, 1781, 2065, 2370, 2696, 3043, 3411, 3800, 4210, 4641, 5093, 5566, 6060, 6575, 7111, 7668, 8246, 8845, 9465, 10106, 10768, 11451, 12155

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. similar sequences listed in A022289.

Programs

Mathematica

Table[n (21 n + 1)/2, {n, 0, 100}] (* Vladimir Joseph Stephan Orlovsky, Mar 07 2011 *)
LinearRecurrence[{3, -3, 1}, {0, 11, 43}, 40] (* Harvey P. Dale, May 06 2014 *)

PARI

a(n)=n*(21*n+1)/2 \\ Charles R Greathouse IV, Jun 16 2017

Formula

a(n) = 21*n + a(n-1) - 10 for n>0, a(0)=0. - Vincenzo Librandi, Aug 04 2010

a(0)=0, a(1)=11, a(2)=43; for n>2, a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3). - Harvey P. Dale, May 06 2014

a(n) = A000217(11*n) - A000217(10*n). - Bruno Berselli, Oct 13 2016

From G. C. Greubel, Aug 23 2017: (Start)

G.f.: x*(10*x + 11)/(1-x)^3.

E.g.f.: (x/2)*(21*x + 22)*exp(x). (End)