OFFSET
0,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..200
FORMULA
a(n) = (16*n^2-4*n-1)*a(n-1) - n*(4*n-6)*a(n-2) for n>1, a(0)=1, a(1)=9.
a(n) = (2n)! * [x^(2n)] exp(-x/2)/(1-2*x)^(5/4).
a(n) = A277358(2*n).
a(n) ~ sqrt(Pi) * 2^(4*n + 13/4) * n^(2*n + 3/4) / (Gamma(1/4) * exp(2*n + 1/4)). - Vaclav Kotesovec, Oct 13 2016
MAPLE
a:= proc(n) option remember; `if`(n<2, 8*n+1,
(16*n^2-4*n-1)*a(n-1)-n*(4*n-6)*a(n-2))
end:
seq(a(n), n=0..15);
MATHEMATICA
a[n_] := a[n] = If[n<2, 8n+1, (16n^2 - 4n - 1) a[n-1] - n (4n-6) a[n-2]];
Table[a[n], {n, 0, 15}] (* Jean-François Alcover, Mar 29 2017, translated from Maple *)
CROSSREFS
KEYWORD
nonn,walk
AUTHOR
Alois P. Heinz, Oct 10 2016
STATUS
approved