A Lambert series is a series of the form F(x) congruent sum_(n = 1)^∞ a_n x^n/(1 - x^n) for left bracketing bar x right bracketing bar <1. Then F(x) | = | sum_(n = 1)^∞ a_n sum_(m = 1)^∞ x^(m n) | = | sum_(N = 1)^∞ b_N x^N, where b_N congruent sum_(n|N) a_n.

divisor function | Erdős-Borwein constant | lambda function | Möbius function | Möbius transform | reciprocal Fibonacci constant | reciprocal Lucas constant | totient function