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Is it, or is it not? (Posted on 2007-04-10) Difficulty: 4 of 5
Is (258+1)/5 an integer? A prime?

See The Solution Submitted by Federico Kereki    
Rating: 3.6667 (3 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re: Just a simple pattern | Comment 6 of 12 |
(In reply to Just a simple pattern by Nishant)

I do not understand

"Now catch this pattern


(2^6+1)/5=13(prime)
(2^14+1)/5=(prime)
(2^22+1)/5=(prime)
(2^30+1)/5=(prime)
......
leaving 2 we have 56 & it is also divisible by 8,but our pattern passes through 54 not through 58 so we conclude X IS NOT A PRIME"

First of all

(2^14+1)/5=3277=29*113
(2^22+1)/5=838,861=397*2113
(2^30+1)/5=214,748,365=5 * 13 * 41 * 61 * 1321

Second, even if they formed a prime pattern, it wouldn't mean there are no primes outside the pattern.


  Posted by Charlie on 2007-04-10 16:42:22
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