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Let's observe following number :

$ 4517\cdot 2^{332192811}+1$

I have noticed :

If $k\cdot 2^{2n+1}+1$ is prime number then $\gcd(k-1,3)=1$ , where $k,n \in Z^{+}$ , so

$\gcd(k-1,3)=1$ should be a necessary condition.

Since $\gcd(4516,3)=1$ this condition is fulfilled.

Proth weight of coefficient $4517$ is $w \approx 0.98199 $ which may be considered to be high value.

I would like to know are there some other necessary conditions that this number has to satisfy , so that might be considered like candidate for prime number ?

1 Answers 1

2

Mathematica:

1: PrimeQ[$4517\cdot2^{332192811} + 1$]

2: False

I guess they use the Miller-Rabin primality test.

  • 1
    Thanks..I know that it is easy to test number using a computer...but I would like to know are there some theoretical conditions similar to the conditions that I mentioned in the text of the question..2011-11-25
  • 1
    Did you look up the wikipedia page I linked? The Miller-Rabin test actually relies on such conditions which are true for primes.2011-11-25
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    Put another way: Miller-Rabin is in fact a *compositeness* test. If `PrimeQ[]` returns `False`, the number is definitely composite.2011-11-25
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    I think that there must be more similar conditions..2011-11-25