174356582399domain: NAppears in sequencesa(0) = 1, a(1) = 1, a(n+1) = (n+1)*a(n) + n.at n=14A020543If n is even, 2(n/2 + 1)! - 1; if n is odd, ((n + 1)/2 + 1)! - 1.at n=25A030494