E.g.f.: exp(3*x)/(1-x)^2.

Terms

a(0) =1a(1) =5a(2) =27a(3) =159a(4) =1029a(5) =7353a(6) =58095a(7) =506691a(8) =4860297a(9) =51023277a(10) =583097859a(11) =7215769575a(12) =96210083853