n! = \Pi{i=1}^{n}: the factorial of a non-negative integer n. nCk = \frac{n!}{k!(n-k)!}: n choose k, k combinations of n nPk = \Pi{i=n-k+1}^{n}: k permutations of n
n! = \Pi{i=1}^{n}: the factorial of a non-negative integer n. nCk = \frac{n!}{k!(n-k)!}: n choose k, k combinations of n nPk = \Pi{i=n-k+1}^{n}: k permutations of n