[ exp(9/22)*n! ].

Terms

a(0) =1a(1) =3a(2) =9a(3) =36a(4) =180a(5) =1083a(6) =7587a(7) =60699a(8) =546297a(9) =5462971a(10) =60092689a(11) =721112275a(12) =9374459578a(13) =131242434103