G.f. A(x) satisfies A(x) = 1 + x*A(x)^4*A(-x)^3.

Terms

a(0) =1a(1) =1a(2) =1a(3) =4a(4) =7a(5) =34a(6) =70a(7) =368a(8) =819a(9) =4495a(10) =10472a(11) =59052a(12) =141778a(13) =814506a(14) =1997688a(15) =11633440a(16) =28989675a(17) =170574723a(18) =430321633a(19) =2552698720a(20) =6503352856a(21) =38832808586a(22) =99726673130a(23) =598724403680