242853811200domain: NAppears in sequencesa(n) = n! * n(n-1)/4.at n=13A001809a(n) = 3*n*n!.at n=13A052673a(1) = 1, a(2) = 2; for n>2, a(n) = 3*(n-2)*(n-2)!.at n=14A083746The simple continued fraction expansion of F(x) := Product_{n >= 0} (1 - x^(4*n+3))/(1 - x^(4*n+1)) when x = (1/2)*(9 - sqrt(77)).at n=23A221367