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freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-351-hexagonal-orchards.english.md
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id, challengeType, isHidden, title, forumTopicId
id challengeType isHidden title forumTopicId
5900f4cb1000cf542c50ffde 5 false Problem 351: Hexagonal orchards 302011

Description

A hexagonal orchard of order n is a triangular lattice made up of points within a regular hexagon with side n. The following is an example of a hexagonal orchard of order 5:

Highlighted in green are the points which are hidden from the center by a point closer to it. It can be seen that for a hexagonal orchard of order 5, 30 points are hidden from the center.

Let H(n) be the number of points hidden from the center in a hexagonal orchard of order n.

H(5) = 30. H(10) = 138. H(1 000) = 1177848.

Find H(100 000 000).

Instructions

Tests

tests:
  - text: <code>euler351()</code> should return 11762187201804552.
    testString: assert.strictEqual(euler351(), 11762187201804552);

Challenge Seed

function euler351() {
  // Good luck!
  return true;
}

euler351();

Solution

// solution required