  <?php

error_reporting(-1);
mb_internal_encoding('utf-8');

$total = 7;
$step  = 4;

$citizens  = range(1, $total);
$positions = array_combine($citizens, $citizens);

while (count($positions) >= $step) {
    var_dump(implode(",",$positions));
    for ($i = 1; $i < $step; $i++) {
        $cur = next($positions);
        
        if ($cur === false) {
            reset($positions);
        }
    }
    unset($positions[$cur]);
    
    if (current($positions) === false) {
        reset($positions);
    }
    
    //  var_dump(current($positions));
    //   print_r($positions);
}
echo "Выигрышные места: ";
echo implode(", ", array_values($positions)) . ". \n";