Pls help understand what this theorem is saying

Question

anonymous · Answer

attachment

anonymous · Answer

here is the definition of pseudo prime

a composite integer $n$ is called a pseudo prime if  $ 2^n \equiv  2 (\mod{n}) $

kc_kennylau · Answer

A pseudoprime is a number that fulfills Fermat's Little Theorem but is not a prime.

anonymous · Answer

yes, i get the definition of pseudo prime.
i have difficulty in understanding what the statement of theorem is saying :|

kc_kennylau · Answer

M stands for Mersenne

anonymous · Answer

i have circled it red in the attached snapshot...

anonymous · Answer

what does it mean a larger one ?

kc_kennylau · Answer

https://en.wikipedia.org/wiki/Mersenne_prime

kc_kennylau · Answer

a larger pseudoprime

kc_kennylau · Answer

http://mathworld.wolfram.com/FermatPseudoprime.html

anonymous · Answer

im not getting it :(
is it saying, if n is a pseudo prime, then 2^n-1 is a larger pseudo prime... ? this statement  is hard to comprehend to me still

kc_kennylau · Answer

That means, $\Large2^{n-1}\equiv1(\mod n)\rightarrow2^{2^n-1}\equiv1(\mod2^n-1)$

kc_kennylau · Answer

Or, if $n$ is a pseudoprime, then $2^n-1$ is also a pseudoprime

anonymous · Answer

yeah, if the statement was like that, it makes much more sense.
the phrase : "...is a larger one " is completely throwing me off

kc_kennylau · Answer

Where are you from? :)

kc_kennylau · Answer

are you freakin kidding me you're ganeshie8?! why? you're banned?

kc_kennylau · Answer

...

kc_kennylau · Answer

why

anonymous · Answer

was reviewing number theory and got stuck on this for a while

anonymous · Answer

simply...  ;)

kc_kennylau · Answer

xD

kc_kennylau · Answer

close it?