Expansion of e.g.f. exp(Sum_{k=1..8} x^k).

Terms

a(0) =1a(1) =1a(2) =3a(3) =13a(4) =73a(5) =501a(6) =4051a(7) =37633a(8) =394353a(9) =4233673a(10) =51683491a(11) =684364341a(12) =9755819833a(13) =148749428413