math sum of squares and square of sum

rust/difference-of-squares/README.md

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+# Difference of Squares
+
+Welcome to Difference of Squares on Exercism's Rust Track.
+If you need help running the tests or submitting your code, check out `HELP.md`.
+
+## Instructions
+
+Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.
+
+The square of the sum of the first ten natural numbers is
+(1 + 2 + ... + 10)² = 55² = 3025.
+
+The sum of the squares of the first ten natural numbers is
+1² + 2² + ... + 10² = 385.
+
+Hence the difference between the square of the sum of the first ten natural numbers and the sum of the squares of the first ten natural numbers is 3025 - 385 = 2640.
+
+You are not expected to discover an efficient solution to this yourself from first principles; research is allowed, indeed, encouraged.
+Finding the best algorithm for the problem is a key skill in software engineering.
+
+## Source
+
+### Created by
+
+- @EduardoBautista
+
+### Contributed to by
+
+- @ashleygwilliams
+- @coriolinus
+- @cwhakes
+- @eddyp
+- @EduardoBautista
+- @efx
+- @ErikSchierboom
+- @IanWhitney
+- @kytrinyx
+- @leoyvens
+- @lutostag
+- @mkantor
+- @nfiles
+- @petertseng
+- @rofrol
+- @stringparser
+- @TheDarkula
+- @xakon
+- @ZapAnton
+
+### Based on
+
+Problem 6 at Project Euler - https://projecteuler.net/problem=6