title: Count Even Length Binary Sequences With Same Sum Of First And Second Half Bits 1
signature: function countEvenLengthBinarySequencesWithSameSumOfFirstAndSecondHalfBits1($n) {
test_code: <?php
  
  
  // SOLUTION CODE 
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  function validateSolution($actual, $expected){
      return abs($actual - $expected) < 1e-09;
  }
  
  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(
        25, 
        126410606437752.0));
      
      printf("TEST-1...%s\n",driver(
        18, 
        9075135300.0));
      
      printf("TEST-2...%s\n",driver(
        17, 
        2333606220.0));
      
      printf("TEST-3...%s\n",driver(
        8, 
        12870.0));
      
      printf("TEST-4...%s\n",driver(
        8, 
        12870.0));
      
  }
  
  main();
  ?>
source_py: def count_even_length_binary_sequences_with_same_sum_of_first_and_second_half_bits_1(n):
      nCr = 1
      res = 1
      for r in range(1, (n + 1)):
          nCr = ((nCr * ((n + 1) - r)) / r)
          res += (nCr * nCr)
      return res
source_cpp: int count_even_length_binary_sequences_with_same_sum_of_first_and_second_half_bits_1(int n) {
    int nCr = 1, res = 1;
    for ( int r = 1;
    r <= n;
    r ++ ) {
      nCr = ( nCr * ( n + 1 - r ) ) / r;
      res += nCr * nCr;
    }
    return res;
  }