1007 B
1007 B
id | challengeType | title |
---|---|---|
5900f4ea1000cf542c50fffc | 5 | Problem 381: (prime-k) factorial |
Description
For example, if p=7, (7-1)! + (7-2)! + (7-3)! + (7-4)! + (7-5)! = 6! + 5! + 4! + 3! + 2! = 720+120+24+6+2 = 872. As 872 mod(7) = 4, S(7) = 4.
It can be verified that ∑S(p) = 480 for 5 ≤ p < 100.
Find ∑S(p) for 5 ≤ p < 108.
Instructions
Tests
tests:
- text: <code>euler381()</code> should return 139602943319822.
testString: assert.strictEqual(euler381(), 139602943319822, '<code>euler381()</code> should return 139602943319822.');
Challenge Seed
function euler381() {
// Good luck!
return true;
}
euler381();
Solution
// solution required