Talk:Fermat number

Some things that might want to be mentioned

Factors are of form $k\cdot 2^{n+2}+1$

$k=jl2^{2n+2}+j+l$ need not be checked as that's the $k$ value form for their products...

Pepin's test ...

$k\equiv 2\pmod 3$ is not a prime when $n$ is even

$k\equiv 1\pmod 3$ is not a prime when $n$ is odd.