There’s evidence that the factorial function has been used in some form since at least 1150 by the Indian mathematician Bhāskara II [3]. In the 18th century, European mathematicians attempted to generalize this function beyond the natural numbers. Daniel Bernoulli, Christian Goldbach and Leonhard Euler were involved in the early attempts and came up with different definitions. In the 19th century Carl Friedrich Gauss, Karl Weierstrass and Adrien-Marie Legendre further contributed to it, th...
