OFFSET
0,4
FORMULA
a(n) = n! * Sum_{k=0..n} (-2*n+3*k-1)^(n-k) * binomial(2*n-2*k+1,k)/( (2*n-2*k+1)*(n-k)! ).
PROG
(PARI) a(n) = n!*sum(k=0, n, (-2*n+3*k-1)^(n-k)*binomial(2*n-2*k+1, k)/((2*n-2*k+1)*(n-k)!));
CROSSREFS
KEYWORD
sign,new
AUTHOR
Seiichi Manyama, Jan 05 2025
STATUS
approved