factorial - nodef/extra-math GitHub Wiki
Find the factorial of a number.
Similar: factorial, binomial, multinomial.
function factorial(n, k?)
// n: a number
// k: denominator factorial [0]
const xmath = require('extra-math');
xmath.factorial(5);
// → 120
xmath.factorial(6);
// → 720
xmath.factorial(7);
// → 5040