# User talk:Simicich

Hmmmmm....I believe that testing is allowed in one's user area?

## Sometimes I wish I screwed up so someone would yell at me.

It might be better than being bored - but I would not do that on purpose.

## September 2011 Hello, and welcome to Wikipedia. Although everyone is welcome to contribute to Wikipedia, at least one of your recent edits, such as the one you made to Triangular number, did not appear to be constructive and has been reverted or removed. Please use the sandbox for any test edits you would like to make, and read the welcome page to learn more about contributing constructively to this encyclopedia. Thank you. Okay, you screwed up - a little bit. But it's apparently just your first offense so no big problem, it's been corrected. Glenn L (talk) 11:22, 25 September 2011 (UTC)

Okay, this is what your edit looked like:

Triangle numbers can be easily computed by adding n to the previous triangle number, starting from 0. 0+1 is the first triangle number, 1+2 is the second, 2+3 is the third and so forth. In the J language the first 10000 triangle numbers can be computed with the phrase +/\i.1e4 - the 10,000th triangle number is 50005000.

First of all, while these are sometimes called "triangle" numbers, notice that after the lede they are usually called "triangular" numbers. Not a major problem.

Second and more importantly, not only is your algorithm at variance with the lede formula

$T_{n}=\sum _{k=1}^{n}k=1+2+3+\dotsb +(n-1)+n={\frac {n(n+1)}{2}};$ it is also incorrect. The triangular numbers correctly begin with 0+1=1, 1+2=3, 3+3=6, 6+4=10, et cetera. Your result for the 10,000th triangular is correct, but it is much easier to calculate it from the formula:

$T_{10000}=\sum _{k=1}^{10000}k=1+2+3+\dotsb +9999+10000={\frac {10000\times 10001}{2}}=5000\times 10001=50005000.$ I hope this explains my reversion of your edit. — Glenn L (talk) 06:59, 28 September 2011 (UTC)

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