every nth-second display just one second of array

x.js

sequence = ['1st','2nd','3rd','4th','5th','6th'];
 
function displaySequence(round, callback, i){

  var i = i ? i : 0;
  if (i===round) { callback(); return; }
  console.log(sequence[i] + ' > add');
  
  setTimeout(function(){
    console.log(sequence[i] + ' > rmv');
    displaySequence(round, callback, ++i);
  }, 2000);
 
}
 
displaySequence(4, function(){
    console.log('end!');
});