400359733068domain: NAppears in sequencesG.f. A(x) satisfies: A(x) = x/f(x,A(x)) where f(,) is Ramanujan's theta function; i.e., A(x) = x/Sum_{n=-oo,+oo} x^(n*(n+1)/2)*A(x)^(n*(n-1)/2).at n=18A107944