Originally Posted by
lastwish 
hmmm..from what i think you are asking....i believe its:
(S-1)S + S = N
-------
2
S>1
Check if it works...haven't done calculus for a long time.
Ya, this this is what I was also saying (except your constant of 1/2 would just be the generic d constant for all cases), but he didn't seem to think an arithmetic series was what he wanted. And I wouldn't really call this calculus. Confused, b/c I think ^this is correct.