- A few months ago, I started to search for twin primes that would be

both generalized Cullen and generalized Woodall numbers. This means

n*a^n+1 and n*a^n-1.

The search was conducted with n from 1 to 10000, and a from 2 to 50.

After a first sieving with Multisieve, only the sets(GC(a,n),GW(a,n))

without small factors have been PRP'ed with PFGW.

Of course some existing primes have been found again, but there are

also new results.

Twin GC/GW : 84*45^84 +/-1

GW :

115*48^115-1 123*20^123-1

132*35^132-1 390*41^390-1

525*48^525-1 795*22^795-1

850*42^850-1 1137*4^1137-1

1568*9^1568-1 4100*36^4100-1

7342*42^7342-1

I hope this will help filling in existing tables on the subject.

BR - None of these are new, but it is nice to have

confirmation of these numbers. I have noted that

84*45^84+/-1 is twin in the list maintained at

http://www.geocities.com/harvey563/GeneralizedWoodallPrimes.txt

Steven Harvey

--- dibo12fr <didier.boivin@...> wrote:> A few months ago, I started to search for twin

=====

> primes that would be

> both generalized Cullen and generalized Woodall

> numbers. This means

> n*a^n+1 and n*a^n-1.

> The search was conducted with n from 1 to 10000, and

> a from 2 to 50.

> After a first sieving with Multisieve, only the

> sets(GC(a,n),GW(a,n))

> without small factors have been PRP'ed with PFGW.

> Of course some existing primes have been found

> again, but there are

> also new results.

> Twin GC/GW : 84*45^84 +/-1

> GW :

> 115*48^115-1 123*20^123-1

> 132*35^132-1 390*41^390-1

> 525*48^525-1 795*22^795-1

> 850*42^850-1 1137*4^1137-1

> 1568*9^1568-1 4100*36^4100-1

> 7342*42^7342-1

>

> I hope this will help filling in existing tables on

> the subject.

> BR

>

>

harvey563@...

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