function get_monthes($month)
{
  $monthes = array($month);
  for($i = 1; $i < 4; $i++) {
      $_month = 12+($month + 3* ( $i-12))%12;	
    $monthes[] = $_month;
  }

  return $monthes;
}

print_r(get_monthes('01'));

$debut=date_create('2015-05-11');
  $fin = clone $debut;
 $fin = $fin->modify( '+12 month' );//ajout de 12 mois à la date debut

 $interval = new DateInterval('P3M');//incrément de 3
 $periode = new DatePeriod($debut, $interval ,$fin);
 foreach($periode as $date){
     $monthes[] =date_format($date,"Y-m") ;
  echo 'mois trim = ', date_format($date,"Y-m") , "<br>";
 }
print_r($monthes);

function get_monthes($month)
{
  $monthes = array($month);
  for($i = 1; $i < 4; $i++) {
    $_month = $month + 3 * $i;
    $_month = $_month > 12 ? $_month - 12 : $_month;
    $_month = $_month < 10 ? "0$_month" : $_month;
	
    $monthes[] = $_month;
  }

  return $monthes;
}

print_r(get_monthes('01'));/* Array ( [0] => 01 [1] => 04 [2] => 07 [3] => 10 ) */
print_r(get_monthes('04'));/* Array ( [0] => 04 [1] => 07 [2] => 10 [3] => 01 ) */
print_r(get_monthes('08'));/* Array ( [0] => 08 [1] => 11 [2] => 02 [3] => 05 ) */
print_r(get_monthes('11'));/* Array ( [0] => 11 [1] => 02 [2] => 05 [3] => 08 ) */