OFFSET
0,3
LINKS
Seiichi Manyama, Table of n, a(n) for n = 0..57
FORMULA
a(n) = [x^(n^2)] (1-x)^(n-1)/((1-x)^n + x^(n+1)).
MATHEMATICA
a[n_] := Sum[(-1)^k * Binomial[n^2 - k, n*k], {k, 0, n}]; Array[a, 13, 0] (* Amiram Eldar, Oct 12 2021 *)
PROG
(PARI) a(n) = sum(k=0, n, (-1)^k*binomial(n^2-k, n*k));
(PARI) a(n) = polcoef((1-x)^(n-1)/((1-x)^n+x^(n+1)+x*O(x^n^2)), n^2);
CROSSREFS
KEYWORD
sign
AUTHOR
Seiichi Manyama, Oct 12 2021
STATUS
approved