G.f. A(x) satisfies: A(x) = 1 + Sum_{k>=1} k*x^k*A(x)^k/(1 + x^k).

Terms

a(0) =1a(1) =1a(2) =2a(3) =9a(4) =28a(5) =109a(6) =440a(7) =1790a(8) =7537a(9) =32300a(10) =140438a(11) =618608a(12) =2753510a(13) =12366672a(14) =55973926a(15) =255059808a(16) =1169143476a(17) =5387268256a(18) =24940059514a(19) =115943355422a(20) =541047868905