[ exp(1/17)*n! ].

Terms

a(0) =1a(1) =2a(2) =6a(3) =25a(4) =127a(5) =763a(6) =5345a(7) =42762a(8) =384866a(9) =3848661a(10) =42335281a(11) =508023378a(12) =6604303919a(13) =92460254879