Can you help me find an equation for this correlation? 2*1+1

3*2+0

4*2+2

5*3+0

6*3+3

7*4+0

8*4+4

9*5+0

10*5+5

This is the way scores are calculated when you play the game Cascade. The more number of balls you manage to "click away", the better score you get. So, I wrote down lots of results for different amount of balls I clicked away. Clicking away one pair (two adjacent) of balls means 3 points. Clicking away three adjacent balls means 6 points. etc. You can see this from the list above.

What I now want to do is to find an equation with only ONE unknown! Y= kn*X+c or something. Whereby I only know X, I can find Y.