[ exp(5/6)*n! ].

Terms

a(0) =2a(1) =4a(2) =13a(3) =55a(4) =276a(5) =1656a(6) =11596a(7) =92775a(8) =834978a(9) =8349781a(10) =91847594a(11) =1102171133a(12) =14328224732a(13) =200595146260