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Old 2016-03-11, 06:48   #12
PawnProver44
 
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That is the only exception:

2^p+p^2 is prime, so p is an odd multiple of 3:

Case 1: p = 1 (mod 3):

2^p+p^2 = 0 (mod 3); 2 (mod 3) + 1 (mod 3) = 0 (mod 3)

Case 2: p = 2 (mod 3):

2^p+p^2 = 0 (mod 3); 2 (mod 3) + 1 (mod 3) = 0 (mod 3)

Case 3: p = 0 (mod 3):

2^p+p^2 = 2 (mod 3); 2 (mod 3) + 0 (mod 3) = 2 (mod 3)

See, I was correct.
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Old 2016-03-11, 07:18   #13
Batalov
 
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Quote:
Originally Posted by PawnProver44 View Post
See, I was correct.
Another false statement. Gee, you are racking them up. Are you proud of being wrong all the time? Like this is some kind of an achievement?

Goodbye. On the "ignore list" you go.
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Old 2017-01-21, 11:52   #14
sweety439
 
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See http://www.primenumbers.net/Henri/us/NouvP1us.htm, there are also no known primes of these forms:

(2^n-k)*2^n+1, for k = 7, 34, 74, 79, ... and is 3 the only n such that (2^n-k)*2^n+1 is prime for k=6? (if (2^n-k)*2^n+1 is prime for k=1, then this n must be 3-smooth)

(2^n+k)*2^n+1 for k = 15. (if (2^n+k)*2^n+1 is prime for k=1, then this k must be a power of 3)

Besides, for (2^n-k)*2^n-1 and (2^n+k)*2^n-1, is there any reserving for them?

Last fiddled with by sweety439 on 2017-01-21 at 11:54
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