Given relatively prime integers p and q (i.e., (p, q) = 1), the Dedekind sum is defined by s(p, q) congruent sum_(i = 1)^q((i/q))(((p i)/q)), where ((x)) congruent {x - ⌊x⌋ - 1/2 | x not element Z 0 | x element Z, auto right match

Dedekind eta function | Iseki's formula

Richard Dedekind