MathDB

D 10

Source:

May 25, 2007

modular arithmeticquadraticsCongruences

Problem Statement

Let

p

be a prime number of the form

4k+1

. Suppose that

2p+1

is prime. Show that there is no

k \in \mathbb{N}

with

k<2p

and

2^k \equiv 1 \; \pmod{2p+1}