How do I generate a variables as below by just entering a number into a function (in this case 5)?

```
  rank  DATE  OP
1    1 DATE1 OP1
2    2 DATE2 OP2
3    3 DATE3 OP3
4    4 DATE4 OP4
5    5 DATE5 OP5
> 

```

Which is the easiest way?