[ exp(9/10)*n! ].

Terms

a(0) =2a(1) =4a(2) =14a(3) =59a(4) =295a(5) =1770a(6) =12396a(7) =99171a(8) =892540a(9) =8925407a(10) =98179485a(11) =1178153825a(12) =15315999732a(13) =214423996260