Pi function

In mathematics, at least four different functions are known as the pi or Pi function:

• <math>\pi(x)\,\!</math> (pi function) – the prime-counting function
• <math>\Pi(x)\,\!</math> (Pi function) – the gamma function when offset to coincide with the factorial
• Rectangular function
• <math>\pi(n)\,\!</math> – the Pisano period

You might also be looking for:

• <math>\prod_{n=1}^{\infty}</math> – the Infinite product of a sequence
• Capital pi notation