114144030000domain: NAppears in sequencesA(n,k) = Sum_{j=0..n} (k*n)!/(j! * (n-j)!)^k, square array A(n,k) read by antidiagonals, for n >= 0, k >= 0.at n=40A306641a(n) = Sum_{k=0..n} (n^2)!/(k! * (n-k)!)^n.at n=4A306644a(n) = Sum_{k=0..n} (4*n)! / (k! * (n-k)!)^4.at n=4A345646