[ exp(7/20)*n! ].

Terms

a(0) =1a(1) =2a(2) =8a(3) =34a(4) =170a(5) =1021a(6) =7152a(7) =57216a(8) =514951a(9) =5149512a(10) =56644635a(11) =679735626a(12) =8836563141a(13) =123711883983