G.f. A(x) satisfies A( x*A(x)^3 + A(x)^5 ) = A(x)^4.

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =15a(5) =49a(6) =168a(7) =594a(8) =2150a(9) =7931a(10) =29718a(11) =112814a(12) =432957a(13) =1677050a(14) =6547856a(15) =25742454a(16) =101819101a(17) =404885649a(18) =1617725220a(19) =6491296371a(20) =26147447557a(21) =105691741392a(22) =428578725720