Reversion of y - y^2 + y^3 - y^4 - y^5.

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =1a(5) =3a(6) =14a(7) =50a(8) =141a(9) =357a(10) =957a(11) =2977a(12) =10023a(13) =33145a(14) =104788a(15) =324700a(16) =1021972a(17) =3313866a(18) =10941283a(19) =36150319a(20) =118733636a(21) =389270860a(22) =1282538880a(23) =4257534180a(24) =14209589940a(25) =47521738212a(26) =159015643218a(27) =532696723370