2452472domain: NAppears in sequencesa(n) = binomial(n+5,5)*(n+3)/3.at n=28A040977Convolution of nonzero triangular numbers (A000217) and nonzero tetradecagonal numbers (A051866).at n=28A271567a(0) = 1; a(n) = n * a(n-1) + (1/n) * Sum_{k=3..n} (binomial(n,k) * k!)^2 * a(n-k) / k.at n=7A346372