[ exp(6/11)*n! ].

Terms

a(0) =1a(1) =3a(2) =10a(3) =41a(4) =207a(5) =1242a(6) =8695a(7) =69567a(8) =626110a(9) =6261104a(10) =68872146a(11) =826465755a(12) =10744054820a(13) =150416767486