727 B
727 B
id, title, challengeType, forumTopicId, dashedName
| id | title | challengeType | forumTopicId | dashedName |
|---|---|---|---|---|
| 5900f5041000cf542c510016 | Problem 407: Idempotents | 5 | 302075 | problem-407-idempotents |
--description--
If we calculate a^2\bmod 6 for 0 ≤ a ≤ 5 we get: 0, 1, 4, 3, 4, 1.
The largest value of a such that a^2 ≡ a\bmod 6 is 4.
Let's call M(n) the largest value of a < n such that a^2 ≡ a (\text{mod } n). So M(6) = 4.
Find \sum M(n) for 1 ≤ n ≤ {10}^7.
--hints--
idempotents() should return 39782849136421.
assert.strictEqual(idempotents(), 39782849136421);
--seed--
--seed-contents--
function idempotents() {
return true;
}
idempotents();
--solutions--
// solution required