891 B

Raw Blame History

id	title	challengeType	forumTopicId	dashedName
5900f4c71000cf542c50ffd8	Problem 346: Strong Repunits	5	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. 710 = 116 = 1112). 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 1012.

--hints--

euler346() should return 336108797689259260.

assert.strictEqual(euler346(), 336108797689259260);

--seed--

--seed-contents--

function euler346() {

  return true;
}

euler346();

--solutions--

// solution required

891 B Raw Blame History