45722880domain: NAppears in sequencesa(n) = n! * binomial(n,4).at n=5A001806a(n) = n! * binomial(n,5).at n=4A001807Diagonal T(s,s) of triangle A059836.at n=9A059837a(n) = ((2*n + 1)! / n!)^2 / (n + 1).at n=4A360602