OFFSET
0,3
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..450
MAPLE
a:= proc(n) option remember; `if`(n<5, [0, 1, 3, 12, 53][n+1],
(2*(2*n^2-9*n+6)*a(n-1) -(2*n^3-13*n^2+21*n-8)*a(n-2)
-(4*n^2-21*n+30)*a(n-3) +(2*n^3-19*n^2+63*n-71)*a(n-4)
-(2*n-5)*(n-4)*a(n-5)) / (2*n-7))
end:
seq(a(n), n=0..23);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Feb 21 2019
STATUS
approved