25480396800domain: NAppears in sequencesa(n) = 2^(2*n)*(n!)^2*Product_{e_k} binomial(2*e_k, e_k) where 2n = Product p_k^e_k is the prime factorization of 2n.at n=5A151932a(n) = A163176(n+1)*A003557(n+1).at n=23A341108