OFFSET
0,2
FORMULA
a(n) = (n^2+11*n+34)/2 + (n-2)*2^(n+3).
G.f.: 1/((1-2*x)^2*(1-x)^3).
a(n) = Sum_{k=1..n+4} Sum_{i=1..n+4} (i-k) * C(n-k+4,i). - Wesley Ivan Hurt, Sep 19 2017
MATHEMATICA
Table[(n^2 + 11 n + 34)/2 + (n - 2)*2^(n + 3), {n, 0, 26}] (* or *)
CoefficientList[Series[1/((1 - 2 x)^2*(1 - x)^3), {x, 0, 26}], x] (* Michael De Vlieger, Sep 21 2017 *)
PROG
(PARI) Vec(1/((1-2*x)^2*(1-x)^3) + O(x^40)) \\ Michel Marcus, Sep 20 2017
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
STATUS
approved