65782211domain: NAppears in sequencesNumber of 4-packed words of degree n.at n=4A243665Number of m-shape ordered set partitions, square array read by ascending antidiagonals, A(m, n) for m, n >= 0.at n=40A260883a(n) = (n^2)! * [x^(n^2)] 1 / (1 - Sum_{k>=1} x^(n*k) / (n*k)!).at n=4A332303