45 lines
990 B
Markdown
45 lines
990 B
Markdown
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---
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id: 5900f3f21000cf542c50ff04
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title: 'Problem 133: Repunit nonfactors'
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challengeType: 5
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forumTopicId: 301761
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dashedName: problem-133-repunit-nonfactors
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---
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# --description--
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A number consisting entirely of ones is called a repunit. We shall define R(k) to be a repunit of length k; for example, R(6) = 111111.
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Let us consider repunits of the form R(10n).
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Although R(10), R(100), or R(1000) are not divisible by 17, R(10000) is divisible by 17. Yet there is no value of n for which R(10n) will divide by 19. In fact, it is remarkable that 11, 17, 41, and 73 are the only four primes below one-hundred that can be a factor of R(10n).
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Find the sum of all the primes below one-hundred thousand that will never be a factor of R(10n).
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# --hints--
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`euler133()` should return 453647705.
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```js
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assert.strictEqual(euler133(), 453647705);
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```
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# --seed--
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## --seed-contents--
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```js
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function euler133() {
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return true;
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}
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euler133();
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```
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# --solutions--
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```js
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// solution required
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```
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