42 lines
641 B
Markdown
42 lines
641 B
Markdown
---
|
||
id: 5900f3e41000cf542c50fef7
|
||
title: 'Problem 120: Square remainders'
|
||
challengeType: 5
|
||
forumTopicId: 301747
|
||
---
|
||
|
||
# --description--
|
||
|
||
Let r be the remainder when (a−1)n + (a+1)n is divided by a2.
|
||
|
||
For example, if a = 7 and n = 3, then r = 42: 63 + 83 = 728 ≡ 42 mod 49. And as n varies, so too will r, but for a = 7 it turns out that rmax = 42.
|
||
|
||
For 3 ≤ a ≤ 1000, find ∑ rmax.
|
||
|
||
# --hints--
|
||
|
||
`euler120()` should return 333082500.
|
||
|
||
```js
|
||
assert.strictEqual(euler120(), 333082500);
|
||
```
|
||
|
||
# --seed--
|
||
|
||
## --seed-contents--
|
||
|
||
```js
|
||
function euler120() {
|
||
|
||
return true;
|
||
}
|
||
|
||
euler120();
|
||
```
|
||
|
||
# --solutions--
|
||
|
||
```js
|
||
// solution required
|
||
```
|