freeCodeCamp/curriculum/challenges/german/10-coding-interview-prep/project-euler/problem-346-strong-repunits.md

id, title, challengeType, forumTopicId, dashedName

id	title	challengeType	forumTopicId	dashedName
5900f4c71000cf542c50ffd8	Problem 346: Strong Repunits	1	302005	problem-346-strong-repunits

--description--

The number 7 is special, because 7 is 111 written in base 2, and 11 written in base 6 (i.e. 7_{10} = {11}_6 = {111}_2). In other words, 7 is a repunit in at least two bases b > 1.

We shall call a positive integer with this property a strong repunit. It can be verified that there are 8 strong repunits below 50: {1, 7, 13, 15, 21, 31, 40, 43}. Furthermore, the sum of all strong repunits below 1000 equals 15864.

Find the sum of all strong repunits below {10}^{12}.

--hints--

strongRepunits() should return 336108797689259260.

assert.strictEqual(strongRepunits(), 336108797689259260);

--seed--

--seed-contents--

function strongRepunits() {

  return true;
}

strongRepunits();

--solutions--

// solution required