freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-409-nim-extreme.english.md

id, challengeType, title, forumTopicId

id	challengeType	title	forumTopicId
5900f5061000cf542c510017	5	Problem 409: Nim Extreme	302077

Description

Let n be a positive integer. Consider nim positions where:There are n non-empty piles. Each pile has size less than 2n. No two piles have the same size. Let W(n) be the number of winning nim positions satisfying the above conditions (a position is winning if the first player has a winning strategy). For example, W(1) = 1, W(2) = 6, W(3) = 168, W(5) = 19764360 and W(100) mod 1 000 000 007 = 384777056.

Find W(10 000 000) mod 1 000 000 007.

Instructions

Tests

tests:
  - text: <code>euler409()</code> should return 253223948.
    testString: assert.strictEqual(euler409(), 253223948);

Challenge Seed

function euler409() {
  // Good luck!
  return true;
}

euler409();

Solution

// solution required