1.6 KiB
1.6 KiB
id | challengeType | title |
---|---|---|
5900f47f1000cf542c50ff91 | 5 | Problem 274: Divisibility Multipliers |
Description
f(n) = (all but the last digit of n) + (the last digit of n) * m
That is, if m is the divisibility multiplier for p, then f(n) is divisible by p if and only if n is divisible by p.
(When n is much larger than p, f(n) will be less than n and repeated application of f provides a multiplicative divisibility test for p.)
For example, the divisibility multiplier for 113 is 34.
f(76275) = 7627 + 5 * 34 = 7797 : 76275 and 7797 are both divisible by 113f(12345) = 1234 + 5 * 34 = 1404 : 12345 and 1404 are both not divisible by 113
The sum of the divisibility multipliers for the primes that are coprime to 10 and less than 1000 is 39517. What is the sum of the divisibility multipliers for the primes that are coprime to 10 and less than 107?
Instructions
Tests
tests:
- text: <code>euler274()</code> should return 1601912348822.
testString: assert.strictEqual(euler274(), 1601912348822, '<code>euler274()</code> should return 1601912348822.');
Challenge Seed
function euler274() {
// Good luck!
return true;
}
euler274();
Solution
// solution required