gistfile1.js

function Sequence(init,n,iter){
  return {
    take:function(x){
      var list=init.slice(0);
      while(x>list.length){
        list.push(iter.apply(null,(n!=Infinity?list.slice(list.length-n):list).concat(list.length)));
      }
      return list
    },
    read:function(x){
      return this.take(x).pop();
    }
  }
}