OFFSET
1,2
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..404
FORMULA
a(n) ~ (1 - exp(-1)) * 2^(n + 1/2) * n^n / exp(n). - Vaclav Kotesovec, Oct 25 2017
MAPLE
a:= proc(n) option remember; `if`(n<3, n, (4*n-6)*
a(n-1)-2*(2*n^2-8*n+7)*a(n-2)-(2*n-5)*a(n-3))
end:
seq(a(n), n=1..25);
CROSSREFS
KEYWORD
nonn
AUTHOR
Alois P. Heinz, Oct 19 2017
STATUS
approved