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A022284
a(n) = n*(27*n - 1)/2.
3
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
0,2
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
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 *)
PROG
(PARI) a(n)=n*(27*n-1)/2 \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
Cf. similar sequences listed in A022288.
Sequence in context: A087880 A228872 A041322 * A179549 A139974 A142188
KEYWORD
nonn,easy
STATUS
approved