OFFSET
0,4
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..27
EXAMPLE
a(2) = (1/2) * (binomial(1+1,1) - binomial(1+2,2) - binomial(2+1,1) + binomial(2+2,2)) = 1.
PROG
(PARI) {a(n) = sum(i=n, n^2, (-1)^i*i!*polcoef(sum(j=1, n, x^j/j!)^n, i))/n!}
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, May 20 2019
STATUS
approved