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

Terms

a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =4a(6) =11a(7) =32a(8) =106a(9) =376a(10) =1433a(11) =5782a(12) =24574a(13) =109393a(14) =508026a(15) =2453256a(16) =12285347a(17) =63656731a(18) =340626704a(19) =1879183856a(20) =10672897341a(21) =62323897482a(22) =373748877678