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

Terms

a(0) =1a(1) =1a(2) =0a(3) =1a(4) =4a(5) =6a(6) =8a(7) =29a(8) =84a(9) =162a(10) =360a(11) =1074a(12) =2808a(13) =6444a(14) =16464a(15) =45629a(16) =118244a(17) =297450a(18) =790184a(19) =2138438a(20) =5624136a(21) =14778068a(22) =39767024a(23) =107287122a(24) =286593800a(25) =768920084a(26) =2083170960a(27) =5642886852a(28) =15250029552a(29) =41369986008