G.f. satisfies: 1 = Sum_{n>=0} (-x)^(n*(n+1)/2) * A(x)^(n+1).

Terms

a(0) =1a(1) =1a(2) =2a(3) =6a(4) =19a(5) =63a(6) =218a(7) =781a(8) =2869a(9) =10742a(10) =40846a(11) =157318a(12) =612446a(13) =2406100a(14) =9527159a(15) =37981611a(16) =152328497a(17) =614167702a(18) =2487941464a(19) =10121128882a(20) =41330709103a(21) =169362297620a(22) =696187639438