Expansion of e.g.f. exp(x+x^2-1/6*x^3).

Terms

a(0) =1a(1) =1a(2) =3a(3) =6a(4) =21a(5) =51a(6) =201a(7) =498a(8) =2241a(9) =4581a(10) =26991a(11) =17766a(12) =359613a(13) =-995409a(14) =6968781a(15) =-53627454a(16) =259953921a(17) =-2292378327a(18) =13839388731a(19) =-108459180954a(20) =809434284741