groupNoAdj

public boolean groupNoAdj(int start, int[] nums, int target) {

  if( start >= nums.length){
    return target==0;
  }

  if(groupNoAdj(start+2, nums, target-nums[start])) return true;
  if(groupNoAdj(start+1, nums, target)) return true;

  return false;

}

http://codingbat.com/prob/p169605