Reversion of x-x^2-x^3-x^4-x^5-x^6.

Terms

a(0) =1a(1) =1a(2) =3a(3) =11a(4) =45a(5) =197a(6) =902a(7) =4269a(8) =20717a(9) =102531a(10) =515521a(11) =2625909a(12) =13521776a(13) =70274194a(14) =368131940a(15) =1941801115a(16) =10304601189a(17) =54976677289a(18) =294708283729