freeCodeCamp/curriculum/challenges/english/08-coding-interview-prep/project-euler/problem-37-truncatable-primes.english.md

id	challengeType	title
5900f3911000cf542c50fea4	5	Problem 37: Truncatable primes

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.

Instructions

Tests

tests:
  - text: <code>truncatablePrimes(8)</code> should return 1986.
    testString: assert(truncatablePrimes(8) == 1986, '<code>truncatablePrimes(8)</code> should return 1986.');
  - text: <code>truncatablePrimes(9)</code> should return 5123.
    testString: assert(truncatablePrimes(9) == 5123, '<code>truncatablePrimes(9)</code> should return 5123.');
  - text: <code>truncatablePrimes(10)</code> should return 8920.
    testString: assert(truncatablePrimes(10) == 8920, '<code>truncatablePrimes(10)</code> should return 8920.');
  - text: <code>truncatablePrimes(11)</code> should return 748317.
    testString: assert(truncatablePrimes(11) == 748317, '<code>truncatablePrimes(11)</code> should return 748317.');

Challenge Seed

function truncatablePrimes(n) {
  // Good luck!
  return n;
}

truncatablePrimes(11);

Solution

// solution required