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

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =6a(6) =21a(7) =68a(8) =186a(9) =495a(10) =1335a(11) =3744a(12) =10870a(13) =32120a(14) =95565a(15) =284830a(16) =850580a(17) =2548436a(18) =7669604a(19) =23192434a(20) =70443076a(21) =214768128a(22) =656857897a(23) =2014416494a(24) =6192794179a(25) =19081689920a(26) =58923909932a(27) =182331403224a(28) =565289067360