problems with increments in arrays

The following code causes an infinite loop and Out of Memory warnings:

  var contents = [1,1,1,2,1,3,2,1,3,1,3,2,4,1,5,1,6,1,6,2,6,3];
  var i = 0;
  for (i = 0; i < contents.length; i = i + 2) {
    print(contents[i]);
    print(contents[i+1]);
  }

The problem has to do with print(contents[i+1]);so I assume the issue is in the use of i+1at that spot.

The following modification exposes the same, bad behaviour:

    print(contents[i]);
    j = i + 1;
    print(contents[j]);