1.2 KiB
1.2 KiB
id | challengeType | title |
---|---|---|
5900f4621000cf542c50ff74 | 5 | Problem 245: Coresilience |
Description
The resilience of a number d > 1 is then φ(d)d − 1 , where φ is Euler's totient function. We further define the coresilience of a number n > 1 as C(n)= n − φ(n)n − 1. The coresilience of a prime p is C(p) = 1p − 1. Find the sum of all composite integers 1 < n ≤ 2×1011, for which C(n) is a unit fraction.
Instructions
Tests
tests:
- text: <code>euler245()</code> should return 288084712410001.
testString: assert.strictEqual(euler245(), 288084712410001, '<code>euler245()</code> should return 288084712410001.');
Challenge Seed
function euler245() {
// Good luck!
return true;
}
euler245();
Solution
// solution required