[ exp(6/17)*n! ].

Terms

a(0) =1a(1) =2a(2) =8a(3) =34a(4) =170a(5) =1024a(6) =7173a(7) =57385a(8) =516468a(9) =5164680a(10) =56811482a(11) =681737791a(12) =8862591291a(13) =124076278077