635361361920domain: NAppears in sequencesa(n) = a(1)*a(n-1) + a(2)*a(n-2) + ...+ a(n-1)*a(1) for n >= 2. Also a(n) = (2^n)*C(n-1), where C = A000108 (Catalan numbers).at n=15A025225First subdiagonal of number array A082137.at n=14A082143A sequence related to Catalan numbers A000108.at n=16A115125