The two-argument Ramanujan function is defined by ϕ(a, n) | congruent | 1 + 2 sum_(k = 1)^n 1/((a k)^3 - a k) | = | 1 - 1/a(H_(-1/a) + H_(1/a) + 2H_n - H_(n - 1/a) - H_(n + 1/a)).

harmonic number | Ramanujan g- and G-functions | Ramanujan theta functions | tau function