Pyramidal Stack

[ag4gt]

Can anyone give me the general formula for the number of can in a pyramidal stack? Say you have a stack of soup cans. The first row (the one on the bottom) of cans has N cans in it. The next row has N-1. This continues until you reach N rows which has 1 can in it.

 

Thanks

[Dave]

It's the equation for the triangle numbers, and is given by:

 

[math]T_n = \frac{n(n+1)}{2}[/math].

[ag4gt]

Thank you very much! That is just what I needed.