156857domain: NAppears in sequencesa(1) = 1, a(n) = Sum_{k=1..n-1} Sum_{d|k} a(d).at n=17A014668Expansion of x/((1 - x - x^4)*(1 - x)^3).at n=28A145132G.f. satisfies: A(x) = Sum_{n>=0} A(x)^n * x^(n^2) * (1 - x^(2*n+1))/(1 - x).at n=16A199409