[ exp(8/23)*n! ].

Terms

a(0) =1a(1) =2a(2) =8a(3) =33a(4) =169a(5) =1019a(6) =7136a(7) =57092a(8) =513832a(9) =5138329a(10) =56521628a(11) =678259545a(12) =8817374087a(13) =123443237218