2018-09-30 22:01:58 +00:00
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---
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id: 5900f51e1000cf542c510030
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title: 'Problem 432: Totient sum'
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2020-11-27 18:02:05 +00:00
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challengeType: 5
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2019-08-05 16:17:33 +00:00
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forumTopicId: 302103
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2021-01-13 02:31:00 +00:00
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dashedName: problem-432-totient-sum
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2018-09-30 22:01:58 +00:00
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---
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2020-11-27 18:02:05 +00:00
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# --description--
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2018-09-30 22:01:58 +00:00
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2020-11-27 18:02:05 +00:00
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Let S(n,m) = ∑φ(n × i) for 1 ≤ i ≤ m. (φ is Euler's totient function)
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2018-09-30 22:01:58 +00:00
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2020-11-27 18:02:05 +00:00
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You are given that S(510510,106 )= 45480596821125120.
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2018-09-30 22:01:58 +00:00
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2020-11-27 18:02:05 +00:00
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Find S(510510,1011). Give the last 9 digits of your answer.
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2018-09-30 22:01:58 +00:00
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2020-11-27 18:02:05 +00:00
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# --hints--
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2018-09-30 22:01:58 +00:00
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2020-11-27 18:02:05 +00:00
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`euler432()` should return 754862080.
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2018-09-30 22:01:58 +00:00
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2020-11-27 18:02:05 +00:00
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```js
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assert.strictEqual(euler432(), 754862080);
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2018-09-30 22:01:58 +00:00
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```
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2020-11-27 18:02:05 +00:00
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# --seed--
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2018-09-30 22:01:58 +00:00
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2020-11-27 18:02:05 +00:00
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## --seed-contents--
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2018-09-30 22:01:58 +00:00
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```js
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function euler432() {
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2020-09-15 16:57:40 +00:00
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2018-09-30 22:01:58 +00:00
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return true;
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}
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euler432();
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```
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2020-11-27 18:02:05 +00:00
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# --solutions--
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2018-09-30 22:01:58 +00:00
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```js
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// solution required
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```
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