by Jobby (Monk)

on Jul 25, 2002 at 21:36 UTC ( [id://185395]=note: print w/replies, xml )

Need Help??

This is an archived low-energy page for bots and other anonmyous visitors. Please sign up if you are a human and want to interact.

Incidentally, the formula for the nth triangular number is actually 1/2*n*(n+1) rather than the 5*n*(n+1) given above.

Now we *can* prove that the sum of two consecutive triangular numbers is a square number:

1/2*n*(n+1) + 1/2*(n+1)*(n+2)
=1/2*(n+1)*(2n+2)
=(n+1)^2

Thought I was going nuts for a second there :)

Comment on Re: Triangle Numbers

Replies are listed 'Best First'.
Re: Re: Triangle Numbers by Anonymous Monk on Jul 25, 2002 at 21:40 UTC
You missed the decimal point in front of the 5.	[reply]
Re^3: Triangle Numbers by Anonymous Monk on Oct 03, 2004 at 12:20 UTC
which one is right	[reply]

Domain Nodelet^?

Node Status^?

node history
Node Type: note [id://185395]
help

Sections^?

Information^?

Find Nodes^?

Leftovers^?

Notices^?

	• hippo	‥ epoptai's answer Re: how do I set a cookie and redirect was blessed by hippo!
	• erzuuli	‥ Anonymous Monks are no longer allowed to use Super Search, due to an excessive use of this resource by robots.