Finding a formula for this data

I'm trying to work out a formula (i dont even know if it possibly exists) but this is the information is have:

The 1st term - 1

The 2nd term - 1

3rd - 1

4th - 2

5th - 2

6th - 2

7th - 2

8th - 2

9th - 3

10th - 3

etc, etc, but basically i realise that the pattern is you square root the term and round down, eg, if u wanted to find the 29th term, u squeare root, so u get 5.39 and round down to 5, so the 29th term is 5.

What i need to know is there a formula for this, not matter how complicated???