G.f. A(x) satisfies: A( x - A(x^3)/x ) = x.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =15a(5) =49a(6) =168a(7) =596a(8) =2170a(9) =8063a(10) =30451a(11) =116545a(12) =451038a(13) =1762065a(14) =6939684a(15) =27523374a(16) =109832228a(17) =440668881a(18) =1776599145a(19) =7193526536a(20) =29240389629a(21) =119276102017a(22) =488106369196