[ exp(3/23)*n! ].

Terms

a(0) =1a(1) =2a(2) =6a(3) =27a(4) =136a(5) =820a(6) =5742a(7) =45937a(8) =413437a(9) =4134377a(10) =45478153a(11) =545737843a(12) =7094591965a(13) =99324287514