title: Hypercube Graph
signature: function hypercubeGraph($n) {
test_code: <?php
  
  
  // SOLUTION CODE 
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function validateSolution($actual, $expected){
      return serialize($actual) == serialize($expected);
  }
  
  function driver($n, $expected){
      try{
        if (validateSolution(PLACEHOLDER_FN_NAME($n), $expected)){
          return "PASSED";
        }
        return "FAILED";
      }
      catch (Exception $exception_obj) {
        return get_class($exception_obj);
      }
  }
  
  function main(){
      printf("TEST-0...%s\n",driver(
        28, 
        268435456));
      
      printf("TEST-1...%s\n",driver(
        45, 
        35184372088832));
      
      printf("TEST-2...%s\n",driver(
        41, 
        2199023255552));
      
      printf("TEST-3...%s\n",driver(
        36, 
        68719476736));
      
  }
  
  main();
  ?>
source_py: def hypercube_graph(n):
      if (n == 1):
          return 2
      return (2 * hypercube_graph((n - 1)))
source_cpp: int hypercube_graph(int n) {
    if ( n == 1 ) return 2;
    return 2 * hypercube_graph ( n - 1 );
  }