I am having great difficulty figuring the followin problem. Your help is appreciated!

Find all primes p such that 2011p = 2+3+4+...+n for some positive integer n

I've goten as far as 2011p = (n(n+1)/2)-1

p= ((n(n+1)/2)-1)/2011 and plugging in various numbers for n.

Am i on the right track?