Hi. Please can you help me? I have three Maths tests next week, and we have a revision sheets which says lots of stuff, and the last one I can't do! It says nth term. I can do nth term all right, but I was wondering if there is an equation for a sequence if each time the gap changes, eg;

8, 11, 15, 20, 26

+3 +4 +5 +6

__n +/- ___.

Thanks. K