A022278 a(n) = n*(21*n-1)/2.

0, 10, 41, 93, 166, 260, 375, 511, 668, 846, 1045, 1265, 1506, 1768, 2051, 2355, 2680, 3026, 3393, 3781, 4190, 4620, 5071, 5543, 6036, 6550, 7085, 7641, 8218, 8816, 9435, 10075, 10736, 11418, 12121

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, A022278.

Cf. similar sequences listed in A022288.

Programs

Mathematica

Table[n (21 n - 1)/2, {n, 0, 100}] (* Vladimir Joseph Stephan Orlovsky, Mar 07 2011 *)

PARI

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

Formula

a(n) = 21*n + a(n-1) - 11 for n > 0, a(0)=0. - Vincenzo Librandi, Aug 04 2010

G.f.: x*(10 + 11*x)/(1 - x)^3. - R. J. Mathar, Aug 04 2016

a(n) = A000217(11*n-1) - A000217(10*n-1). - Bruno Berselli, Oct 17 2016

E.g.f.: (x/2)*(21*x + 20)*exp(x). - G. C. Greubel, Aug 23 2017