[ exp(9/19)*n! ].

Terms

a(0) =1a(1) =3a(2) =9a(3) =38a(4) =192a(5) =1156a(6) =8093a(7) =64749a(8) =582748a(9) =5827489a(10) =64102380a(11) =769228564a(12) =9999971337a(13) =139999598719