[ exp(5/8)*n! ].

Terms

a(0) =1a(1) =3a(2) =11a(3) =44a(4) =224a(5) =1345a(6) =9415a(7) =75327a(8) =677949a(9) =6779490a(10) =74574400a(11) =894892802a(12) =11633606436a(13) =162870490110