1
$\begingroup$

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

I am looking for the name of an operation similar to factorial.

Factorial would be like: 6! = 6*5*4*3*2*1

but if the operator is "+" and not "*", like: 6+5+4+3+2+1

What would I call this?

Edit: Sorry, it seems this was a duplicate question. The answer appears to be "nth triangular number". Although that's really not as satisfying and concise as the word "factorial".

  • 0
    Instead of $n!$ why not write $n\triangle$?2011-09-16

0 Answers 0