181122452domain: NAppears in sequencesG.f. A(x) = Product_{n>=0} F(n), where F(0) = x, F(1) = 1+x, F(2) = 1 + x*(1+x), and F(n+1) = 1 + (F(n-1) - 1)*(F(n) - 1)*F(n) for n > 1.at n=27A350435