OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..27
FORMULA
a(n) = A144510(n,n).
EXAMPLE
a(2) = (1/2) * (binomial(1+1,1) + binomial(1+2,2) + binomial(2+1,1) + binomial(2+2,2)) = 7.
PROG
(PARI) {a(n) = sum(i=n, n^2, i!*polcoef(sum(j=1, n, x^j/j!)^n, i))/n!}
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 19 2019
STATUS
approved