I am trying to come up with an equation that describes groups of three. I have one limitation though, which is that I have to use an ever increasing value of n + 1 for each iteration. Not sure if this is possible.
So for example:
when n = x : result y
n = 1 : 1 (first set of three)
n = 2 : 2
n = 3 : 3
................................
n = 4 : 7 (second set of three)
n = 5 : 8
n = 6 : 9
................................
n = 7 : 13 (continues...)
The limitation is for a computer program that selects rows. I can provide it with an equation that consists of one variable, n. I would really appreciate not just an answer, but a short explanation of how to tackle it.