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---
id: 5900f3911000cf542c50fea4
challengeType: 5
title: 'Problem 37: Truncatable primes'
---
## Description
< section id = 'description' >
The number 3797 has an interesting property. Being prime itself, it is possible to continuously remove digits from left to right, and remain prime at each stage: 3797, 797, 97, and 7. Similarly we can work from right to left: 3797, 379, 37, and 3.
Find the sum of the only n (8 < = n < = 11) primes that are both truncatable from left to right and right to left.
NOTE: 2, 3, 5, and 7 are not considered to be truncatable primes.
< / section >
## Instructions
< section id = 'instructions' >
< / section >
## Tests
< section id = 'tests' >
```yml
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tests:
- text: < code > truncatablePrimes(8)</ code > should return 1986.
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testString: assert(truncatablePrimes(8) == 1986, '< code > truncatablePrimes(8)< / code > should return 1986.');
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- text: < code > truncatablePrimes(9)</ code > should return 5123.
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testString: assert(truncatablePrimes(9) == 5123, '< code > truncatablePrimes(9)< / code > should return 5123.');
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- text: < code > truncatablePrimes(10)</ code > should return 8920.
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testString: assert(truncatablePrimes(10) == 8920, '< code > truncatablePrimes(10)< / code > should return 8920.');
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- text: < code > truncatablePrimes(11)</ code > should return 748317.
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testString: assert(truncatablePrimes(11) == 748317, '< code > truncatablePrimes(11)< / code > should return 748317.');
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```
< / section >
## Challenge Seed
< section id = 'challengeSeed' >
< div id = 'js-seed' >
```js
function truncatablePrimes(n) {
// Good luck!
return n;
}
truncatablePrimes(11);
```
< / div >
< / section >
## Solution
< section id = 'solution' >
```js
// solution required
```
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< / section >