Pi function

In mathematics, three different functions are known as the pi or Pi function:

You might also be looking for:
 * $$\pi(x)\,\!$$ (pi function) – the prime-counting function
 * $$\Pi(x)\,\!$$ (Pi function) – the gamma function when offset to coincide with the factorial
 * Rectangular function


 * $$\prod_{n=1}^{\infty}$$ – the Infinite product of a sequence
 * Capital pi notation