Sunday, 24 June 2018

Odd number $N$ which does not divide $2^k-1$


Prove that there does not exist a composite odd number $N > 1$ which does not divide $2^k-1$ for $k = 1,2,\ldots,N-2$.




I conjectured this result, but wasn't sure how to prove it. I tried it for many cases and it seems to be true.

No comments:

Post a Comment

real analysis - How to find $lim_{hrightarrow 0}frac{sin(ha)}{h}$

How to find $\lim_{h\rightarrow 0}\frac{\sin(ha)}{h}$ without lhopital rule? I know when I use lhopital I easy get $$ \lim_{h\rightarrow 0}...