完全数とは　それを求めるPHPコードも

$number = 1;
$perfectNumber = array();

for($i = 1; $i < 500; $i++){
    
    $verification = 0;
    $formula = '';
    for($j = 1;$j <= ($number / 2);$j++){ if($number % $j == 0){ $verification += $j; if($formula != '') $formula.= ' + '; $formula .= $j; } } if($number == $verification){ $perfectNumber[$number] = $formula; } if($number == ($verification + 1)){ $semiPerfectNumber[$number] = $formula; } $number++; } echo "完全数は\n"; foreach ($perfectNumber as $number => $formula){
    echo $number . '  【約数の和】' . $formula . "\n";
}

echo "完全数に近い数は\n";

foreach ($semiPerfectNumber as $number => $formula){
    echo $number . '  【約数の和】' . $formula . "\n";
}