OFFSET
0,1
LINKS
Jianing Song, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (6,-12,8).
FORMULA
a(n) = Sum_{k=0..n} binomial(n,k) * (k^2+7*k+8)/2.
G.f.: (2 - 3*x)^2/(1 - 2*x)^3.
E.g.f.: exp(2*x) * (x^2/2 + 4*x + 4).
MATHEMATICA
a[n_] := (n^2 + 15*n + 32)*2^(n - 3); Array[a, 31, 0] (* Amiram Eldar, Nov 08 2021 *)
PROG
(PARI) a(n) = (n^2+15*n+32)*2^(n-3)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Jianing Song, Nov 07 2021
STATUS
approved