567839904255domain: NAppears in sequencesa(n) = [x^n] G(n-1,x) where G(n,x) is the n-th iteration of G(1,x) = x/(1-x+x^2), so that G(n,x) = G(n-1, G(1,x)) with G(0,x)=x.at n=13A242573