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A022278 a(n) = n*(21*n-1)/2. 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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

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).

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

MATHEMATICA

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

PROG

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

CROSSREFS

Cf. A000217, A022278.

Cf. similar sequences listed in A022288.

Sequence in context: A016082 A003355 A247201 * A246972 A266396 A006323

Adjacent sequences:  A022275 A022276 A022277 * A022279 A022280 A022281

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified June 15 22:19 EDT 2019. Contains 324145 sequences. (Running on oeis4.)