Expansion of e.g.f.: exp(x / (1-x)^x).

Terms

a(0) =1a(1) =1a(2) =1a(3) =7a(4) =37a(5) =221a(6) =1801a(7) =15709a(8) =157641a(9) =1775521a(10) =21898801a(11) =296379931a(12) =4346295757a(13) =68682481141