G.f. A(x) satisfies: A(x) = x + x^2 + x^3 + x^4 + x^5 * (1 + A(A(x))).

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =1a(6) =2a(7) =4a(8) =8a(9) =16a(10) =32a(11) =66a(12) =143a(13) =333a(14) =838a(15) =2250a(16) =6320a(17) =18275a(18) =53925a(19) =161957a(20) =495898a(21) =1554159a(22) =5008758a(23) =16662249a(24) =57311722a(25) =203662894a(26) =745602490a(27) =2801326407a(28) =10760995574a(29) =42141768601