[ exp(7/13)*n! ].

Terms

a(0) =1a(1) =3a(2) =10a(3) =41a(4) =205a(5) =1233a(6) =8635a(7) =69083a(8) =621747a(9) =6217472a(10) =68392202a(11) =820706435a(12) =10669183662a(13) =149368571272