G.f. A(x) satisfies: A(x) = x * exp(Sum_{i>=1} Sum_{j>=1} (-1)^(j+1)*A(x^(i*j))/j).

Terms

a(0) =1a(1) =1a(2) =2a(3) =5a(4) =11a(5) =26a(6) =65a(7) =161a(8) =412a(9) =1074a(10) =2841a(11) =7599a(12) =20582a(13) =56202a(14) =154760a(15) =429052a(16) =1196802a(17) =3356107a(18) =9456737a(19) =26760173a(20) =76017365a(21) =216693521a(22) =619663800a(23) =1777141141a(24) =5110235884a(25) =14730604451a(26) =42557910762a(27) =123210505445a(28) =357403386959