<section id="description">
Pentagonal numbers are generated by the formula, Pn=<var>n</var>(3<var>n</var>−1)/2. The first ten pentagonal numbers are:1, 5, 12, 22, 35, 51, 70, 92, 117, 145, ...
It can be seen that P4 + P7 = 22 + 70 = 92 = P8. However, their difference, 70 − 22 = 48, is not pentagonal.
Find the pair of pentagonal numbers, Pj and Pk, for which their sum and difference are pentagonal and D = |Pk − Pj| is minimised; what is the value of D?</section>

function pentagonNumbers() {
  // Good luck!
  return true;
}

pentagonNumbers();


index

Задача 44: номера Пентагона

Problem 44: Pentagon numbers

<code>pentagonNumbers()</code> should return 5482660.