Sorry, an error occurred while loading the content.

## Can anybody say how?

Expand Messages
• for prime(N) if gap = 3 then both 2N + 1 and 2N + 7 are composite and their prime factor either 3 or 5 or 3 and 5.And the converse is not true. Send instant
Message 1 of 3 , May 31, 2006
for prime(N) if gap = 3 then both 2N + 1 and 2N + 7 are composite and their prime factor either 3 or 5 or 3 and 5.And the converse is not true.

Send instant messages to your online friends http://uk.messenger.yahoo.com

[Non-text portions of this message have been removed]
• for prime(N) if gap = 3 then both 2N + 1 and 2N + 7 are composite and their prime factor either 3 or 5 or 3 and 5.And the converse is not true.
Message 2 of 3 , May 31, 2006
for prime(N) if gap = 3 then both 2N + 1 and 2N + 7 are composite and
their prime factor either 3 or 5 or 3 and 5.And the converse is not
true.
• ... 3 always divides one of N, N+2, N+4. By gap = 3 I assume you mean that N and N+4 are consecutive primes. Then 3 must divide N+2. And then 3 divides
Message 3 of 3 , May 31, 2006
kadickv wrote:
> for prime(N) if gap = 3 then both 2N + 1 and 2N + 7 are composite and
> their prime factor either 3 or 5 or 3 and 5.

3 always divides one of N, N+2, N+4.
By "gap = 3" I assume you mean that N and N+4 are consecutive primes.
Then 3 must divide N+2. And then 3 divides 2*(N+2) = 2N+4.
This means 3 also divides 2N+1 and 2N+7.

We know that 5 doesn't divide 2N or 2*(N+4) = 2N+8.
Then 5 must divide exactly one of 2N+1, 2N+4, 2N+7.

--
Jens Kruse Andersen
Your message has been successfully submitted and would be delivered to recipients shortly.