php and c 64 length hexadecimal combination generator

   function everyCombination($array) {
   $arrayCount      = count($array);
   $maxCombinations = pow($arrayCount, $arrayCount);
   $returnArray     = array();
   $conversionArray = array();
   foreach ($array as $key => $value) {
   $conversionArray[base_convert($key, 10, $arrayCount)] = $value;
   }
   $start = 10000;
   $end = 10005;
   for ($i = $start; $i < $end; $i++) {
   $combination = base_convert($i, 10, $arrayCount);
   $combination = str_pad($combination, 64, "0", STR_PAD_LEFT);
   $returnArray[] = strtr($combination, $conversionArray);
   }
   return $returnArray;
   }

   print_r(everyCombination(array('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F')));

output

Array ( [0] => 0000000000000000000000000000000000000000000000000000000000002710 [1] => 0000000000000000000000000000000000000000000000000000000000002711 [2] => 0000000000000000000000000000000000000000000000000000000000002712 [3] => 0000000000000000000000000000000000000000000000000000000000002713 [4] => 0000000000000000000000000000000000000000000000000000000000002714 )

above php code generating combination of 64 length hexadecimal given start value and end value, but some value later it cannot generate combination

if

$start = 9919999999999999903; $end = 9919999999999999913; ---> means it provide

output --> Array ( )

what problem in this code and i need all possible 64 length hexadecimal combination from given start and end value

AND the same time i need this code in C program

any result thank to all