Sanoja: Gilbert Osullivan. Number 4.

Number 4 In the beginning
There was one--
Himself had just began
Then along came Number 2--
The other way round is your clue
And after that came 3--
Written by you know me
Now I'm not saying anymore
Except to tell you

That this is not Number 1: number2:
Number 3: or Number 5 But Number 4