Peter Bengtsson secondary student 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. I am lost! How can this be done?? Can one use the Remainder Theorem for this? Any ideas? Hi Peter, Your numbers are 2*1+1 = 3 3*2+0 = 6 4*2+2 = 10 5*3+0 = 15 6*3+3 = 21 7*4+0 = 28 8*4+4 = 36 9*5+0 = 45 10*5+5 = 55 These are the number of ways to choose 2 objects from n+1 objects,  (n+1)C2. The value of  (n+1)C2 is (n+1)n/2. Cheers, Nom Go to Math Central