freeCodeCamp

id	challengeType	title	forumTopicId	localeTitle
5900f5271000cf542c51003a	5	Problem 443: GCD sequence	302115	Задача 443: последовательность GCD

Description

Let g(n) be a sequence defined as follows: g(4) = 13, g(n) = g(n-1) + gcd(n, g(n-1)) for n > 4.

The first few values are:

n 4567891011121314151617181920... g(n) 1314161718272829303132333451545560...

You are given that g(1 000) = 2524 and g(1 000 000) = 2624152.

Find g(1015).

tests:
  - text: <code>euler443()</code> should return 2744233049300770.
    testString: assert.strictEqual(euler443(), 2744233049300770);

function euler443() {
  // Good luck!
  return true;
}

euler443();

// solution required