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What is the term for a factorial type operation, but with summation instead of products?

We're all familiar with factorial: $$n>0,\quad n! = n \times (n-1) \times \cdots \times (n-(n-1))$$

I've occasionally seen "plustorial": $$n>0,\quad n(\mathrm{plustorial}) = n + (n-1) + \ldots + (n-(n-1))$$

Some quick web searching indicates that there is some non-standard but somewhat common usage of the term "plustorial" to describe this, with shorthand being a double-dagger or an exclaimation point having a "+" rather than a dot beneath the vertical mark.

My question is: Is there a "real" standard name for this process and is there a standard corresponding shorthand? I understand that it could be written in sigma notation, was curious about something more terse.

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    You might want to read a little about triangular numbers. $$1+2+3+\cdots+n = T_n = {n+1 \choose 2} = \frac{n(n+1)}{2}$$2012-06-05
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    thank you, vote to close as "exact duplicate" please. I would think I shouldn't delete the question because others may search using "plustorial" as I did.2012-06-05

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