G.f. satisfies: A(x + x*A(-x)) = x + x*A(x).

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =10a(5) =28a(6) =92a(7) =328a(8) =1330a(9) =5740a(10) =27596a(11) =139160a(12) =769964a(13) =4423736a(14) =27567048a(15) =177127440a(16) =1223262698a(17) =8667225836a(18) =65523382052a(19) =506370134232