G.f. satisfies A(x) = 1 + x*A(x) + x^2*(1-x)^3*A(x)^5.

Terms

a(0) =1a(1) =1a(2) =2a(3) =4a(4) =12a(5) =36a(6) =126a(7) =442a(8) =1644a(9) =6172a(10) =23801a(11) =92731a(12) =366688a(13) =1462852a(14) =5891808a(15) =23898576a(16) =97600556a(17) =400844140a(18) =1654818768a(19) =6862550360a(20) =28576414261a(21) =119434041561a(22) =500849380048