[ exp(7/22)*n! ].

Terms

a(0) =1a(1) =2a(2) =8a(3) =32a(4) =164a(5) =989a(6) =6928a(7) =55424a(8) =498824a(9) =4988243a(10) =54870677a(11) =658448135a(12) =8559825756a(13) =119837560586