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* fix: clean-up Project Euler 241-260 * fix: typo * Update curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-255-rounded-square-roots.md Co-authored-by: Tom <20648924+moT01@users.noreply.github.com>
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id, title, challengeType, forumTopicId, dashedName
| id | title | challengeType | forumTopicId | dashedName |
|---|---|---|---|---|
| 5900f45f1000cf542c50ff71 | Problem 242: Odd Triplets | 5 | 301889 | problem-242-odd-triplets |
--description--
Given the set {1,2,..., $n$}, we define f(n, k) as the number of its $k$-element subsets with an odd sum of elements. For example, f(5,3) = 4, since the set {1,2,3,4,5} has four 3-element subsets having an odd sum of elements, i.e.: {1,2,4}, {1,3,5}, {2,3,4} and {2,4,5}.
When all three values n, k and f(n, k) are odd, we say that they make an odd-triplet [n, k, f(n, k)].
There are exactly five odd-triplets with n ≤ 10, namely: [1, 1, f(1, 1) = 1], [5, 1, f(5, 1) = 3], [5, 5, f(5, 5) = 1], [9, 1, f(9, 1) = 5] and [9, 9, f(9, 9) = 1].
How many odd-triplets are there with n ≤ {10}^{12}?
--hints--
oddTriplets() should return 997104142249036700.
assert.strictEqual(oddTriplets(), 997104142249036700);
--seed--
--seed-contents--
function oddTriplets() {
return true;
}
oddTriplets();
--solutions--
// solution required