For each s, this function gives an infinite sum, which takes some basic calculus to approach for even the simplest values of s. For example, if s=2, then (s) is the well-known series 1 + 1/4 + 1/9 + 1/16 + …, which strangely adds up to exactly ²/6. When s is a complex number—one that looks like a+b, using the imaginary number —finding (s) gets tricky.