OFFSET
0,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..5000
Sela Fried, Counting r X s rectangles in nondecreasing and Smirnov words, arXiv:2406.18923 [math.CO], 2024. See p. 5.
Index entries for linear recurrences with constant coefficients, signature (3,-3,1).
FORMULA
a(n) = (3*n^2 + 19*n)/2.
a(n) = 3*n + a(n-1) + 8 for n>0, a(0)=0. - Vincenzo Librandi, Aug 03 2010
G.f.: x*(11 - 8*x)/(1 - x)^3. - Arkadiusz Wesolowski, Dec 24 2011
E.g.f.: (1/2)*(3*x^2 + 22*x)*exp(x). - G. C. Greubel, Jul 17 2017
MATHEMATICA
Table[(n(3n+19))/2, {n, 0, 50}] (* or *) LinearRecurrence[{3, -3, 1}, {0, 11, 25}, 50] (* Harvey P. Dale, Apr 26 2018 *)
PROG
(PARI) a(n)=n*(3*n+19)/2 \\ Charles R Greathouse IV, Jun 17 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Omar E. Pol, May 22 2008
STATUS
approved