49 lines
827 B
Markdown
49 lines
827 B
Markdown
---
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id: 5900f40d1000cf542c50ff1f
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title: 'Problem 160: Factorial trailing digits'
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challengeType: 5
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forumTopicId: 301794
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dashedName: problem-160-factorial-trailing-digits
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---
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# --description--
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For any $N$, let $f(N)$ be the last five digits before the trailing zeroes in $N!$.
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For example,
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$$\begin{align}
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& 9! = 362880 \\; \text{so} \\; f(9) = 36288 \\\\
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& 10! = 3628800 \\; \text{so} \\; f(10) = 36288 \\\\
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& 20! = 2432902008176640000 \\; \text{so} \\; f(20) = 17664
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\end{align}$$
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Find $f(1,000,000,000,000)$
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# --hints--
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`factorialTrailingDigits()` should return `16576`.
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```js
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assert.strictEqual(factorialTrailingDigits(), 16576);
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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 factorialTrailingDigits() {
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return true;
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}
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factorialTrailingDigits();
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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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