freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-383-divisibility-comparison-between-factorials.english.md
mrugesh 22afc2a0ca feat(learn): python certification projects (#38216)
Co-authored-by: Oliver Eyton-Williams <ojeytonwilliams@gmail.com>
Co-authored-by: Kristofer Koishigawa <scissorsneedfoodtoo@gmail.com>
Co-authored-by: Beau Carnes <beaucarnes@gmail.com>
2020-05-27 13:19:08 +05:30

974 B

id, challengeType, isHidden, title, forumTopicId
id challengeType isHidden title forumTopicId
5900f4ed1000cf542c50ffff 5 false Problem 383: Divisibility comparison between factorials 302047

Description

Let f5(n) be the largest integer x for which 5x divides n. For example, f5(625000) = 7.

Let T5(n) be the number of integers i which satisfy f5((2·i-1)!) < 2·f5(i!) and 1 ≤ i ≤ n. It can be verified that T5(103) = 68 and T5(109) = 2408210.

Find T5(1018).

Instructions

Tests

tests:
  - text: <code>euler383()</code> should return 22173624649806.
    testString: assert.strictEqual(euler383(), 22173624649806);

Challenge Seed

function euler383() {
  // Good luck!
  return true;
}

euler383();

Solution

// solution required