2018-10-10 22:03:03 +00:00
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---
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id: 5900f4521000cf542c50ff64
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2020-12-16 07:37:30 +00:00
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title: 问题229:使用正方形的四个表示
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2018-10-10 22:03:03 +00:00
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challengeType: 5
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videoUrl: ''
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2021-01-13 02:31:00 +00:00
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dashedName: problem-229-four-representations-using-squares
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2018-10-10 22:03:03 +00:00
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---
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2020-12-16 07:37:30 +00:00
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# --description--
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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考虑数字3600.这是非常特别的,因为
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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3600 = 482 + 362 3600 = 202 + 2×402 3600 = 302 + 3×302 3600 = 452 + 7×152
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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类似地,我们发现88201 = 992 + 2802 = 2872 + 2×542 = 2832 + 3×522 = 1972 + 7×842。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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在1747年,欧拉证明哪些数字可以表示为两个正方形的总和。我们感兴趣的是数字n,它承认以下四种类型的表示:
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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n = a12 + b12n = a22 + 2 b22n = a32 + 3 b32n = a72 + 7 b72,
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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其中ak和bk是正整数。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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有75373这样的数字不超过107。
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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有多少这样的数字不超过2×109?
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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# --hints--
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2018-10-10 22:03:03 +00:00
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2020-12-16 07:37:30 +00:00
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`euler229()`应该返回11325263。
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2018-10-10 22:03:03 +00:00
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```js
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2020-12-16 07:37:30 +00:00
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assert.strictEqual(euler229(), 11325263);
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2018-10-10 22:03:03 +00:00
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```
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2020-08-13 15:24:35 +00:00
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2021-01-13 02:31:00 +00:00
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# --seed--
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## --seed-contents--
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```js
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function euler229() {
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return true;
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}
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euler229();
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```
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2020-12-16 07:37:30 +00:00
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# --solutions--
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2021-01-13 02:31:00 +00:00
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```js
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// solution required
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```
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