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coding-corner/2017-04-11/ikselven_euler87-foreach.php

35 lines
717 B
PHP
Executable file

#!/usr/bin/php
<?php
define("MAX", 5*(10**7));
$nextPrime = 2;
$primes = array($nextPrime);
while ($nextPrime < sqrt(MAX)) {
$nextPrime = gmp_intval(gmp_nextprime($nextPrime));
$primes[] = $nextPrime;
}
$sums = array();
foreach($primes as $outer) {
$fourth = $outer ** 4;
if ($fourth >= MAX) {
break;
}
foreach($primes as $middle) {
$cube = $fourth + $middle ** 3;
if ($cube >= MAX) {
break;
}
foreach($primes as $inner) {
$sum = $cube + $inner ** 2;
if ($sum >= MAX) {
break;
}
$sums[] = $sum;
}
}
}
echo "Found ".count(array_unique($sums))." numbers\n";