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<?php
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function sumDivs ($n) {
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$sum = 1;
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for ($d = 2; $d <= sqrt($n); $d++) {
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if ($n % $d == 0) $sum += $n / $d + $d;
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}
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return $sum;
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}
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for ($n = 2; $n < 20000; $n++) {
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$m = sumDivs($n);
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if ($m > $n) {
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if (sumDivs($m) == $n) echo $n." ".$m."<br />";
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}
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}
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?>
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