I have a vector of length 26 and want to split it into groups of length 5. I can write it in code but what's the math notation for breaking a set up into n length groups keeping the elements consecutively ordered?

Using what Bryan Goodrich wrote here: http://www.talkstats.com/showthread....l=1#post178934

I know I have a set of length 26 which I could write as:

How can I say split *d* in to groups of 5? It seems d/5 isn't really what I'm doing so I don't think that's the right notation (especially since the sub groups need to be consecutive).