566828686621domain: NAppears in sequencesa(n) = (3*(n-1)+3)! *(3*(n-1)+6)! *2F2(3*n+1,3*n+4; 4,7; 1)/( 3! *6! *exp(1)), where 2F2(;;) is the generalized hypergeometric series.at n=2A072679