Thread: Summation of summation?

I want to figure out the proper summation to figure out a sum of products:
5
x3
----
15
x3
----
45
x3
----
135
x3
___
...

So if n=0 the result is 5, if n=1 the result is 5+15, if n=2, the result is 5+15+45 and so. Hopefully that makes sense. I'm not quite sure how else to put it. Would the best way be to do something like ? Or is there some more concise way of putting it? I appreciate any help you guys can offer. Thanks.

Originally Posted by blcArmadillo

I want to figure out the proper summation to figure out a sum of products:
5
x3
----
15
x3
----
45
x3
----
135
x3
___
...

So if n=0 the result is 5, if n=1 the result is 5+15, if n=2, the result is 5+15+45 and so. Hopefully that makes sense. I'm not quite sure how else to put it. Would the best way be to do something like ? Or is there some more concise way of putting it? I appreciate any help you guys can offer. Thanks.

Try