# programming-environment

 Random Link ¯\_(ツ)_/¯ Jan 15, 2022 » 020. Factorial Digit Sum 4 min; updated Jan 15, 2022 Problem Statement $$n!$$ means $$n \times (n - 1) \times … \times 3 \times 2 \times 1$$. For example, $$10! = 10 \times 9 \times … \times 3 \times 2 \times 1 = 3628800$$, and the sum of the digits in the number $$10!$$ is $$3 + 6 + 2 + 8 + 8 + 0 + 0 = 27$$. Find the sum of the digits in the number $$100!... Feb 6, 2021 » 021. Amicable Numbers 8 min; updated Feb 6, 2021 Problem Statement Let \(d(n)$$ be defined as the sum of proper divisors of $$n$$ (numbers less than $$n$$ which divide evenly into $$n$$). If $$d(a) = b$$ and $$d(b) = a$$, where $$a \neq b$$, then $$a$$ and $$b$$ are an amicable pair and each of $$a$$ and $$b$$ are called amicable numbers. For example, the proper divisors of $$220$$ are $$1, 2, 4, 5, 10, 11, 20, 22, 44, 55, 110$$; therefore $$d(220) = 284$$....