G.f. A(x) satisfies: 1 = Sum_{n>=0} x^n * (1 + n*x)^n / A(x)^(n+1).

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =3a(5) =9a(6) =21a(7) =76a(8) =241a(9) =962a(10) =3687a(11) =15930a(12) =68993a(13) =320025a(14) =1511977a(15) =7471685a(16) =37780922a(17) =197506241a(18) =1056928087a(19) =5810534182a(20) =32667061545a(21) =187952045908