OFFSET
0,2
FORMULA
G.f.: 1/(((1-2*x)^2)*(1-x)^5).
a(n) = A055249(n+6, 6).
For n >= 1, a(n) = A035038(n+6) + Sum_{j=0..n-1} a(j).
a(n) = Sum_{k=0..n+5} Sum_{i=0..n+5} (i-k) * C(n-k+5,i+3). - Wesley Ivan Hurt, Sep 19 2017
MAPLE
a:= n-> (Matrix(7, (i, j)-> if (i=j-1) then 1 elif j=1 then [9, -34, 70, -85, 61, -24, 4][i] else 0 fi)^(n))[1, 1]: seq(a(n), n=0..25); # Alois P. Heinz, Aug 05 2008
MATHEMATICA
Table[Sum[(-1)^(n - k) k (-1)^(n - k) Binomial[n + 5, k + 5], {k, 0, n}], {n, 1, 26}] (* Zerinvary Lajos, Jul 08 2009 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Wolfdieter Lang, May 26 2000
STATUS
approved