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Old 2020-09-08, 06:41   #370
kar_bon
 
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Mar 2006
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1281979*2^n-1 has a Nash weight of 1789, so relatively low.
1281979 \equiv 1 mod 3 so all primes of that sequence are only odd n-values.
k-values with 2 mod 3 can only produce primes with even n's, and k's divisible by 3 can produce primes with odd/even n-values.

1281979*2^n+1 has a low Nash weight of 847, so there should less primes for this sequence.

The Liskovets-Gallot conjectures study the contribution of odd/even n-values of such seqs.
There exits k-values which never produce primes for any n-value like the Riesel problem.

PS: If your're done you can list the prime n-values in this thread and I can include those in the Wiki, both sides (Proth /Riesel) possible. Don't forget to give the search limits then.

Last fiddled with by kar_bon on 2020-09-08 at 06:47 Reason: PS
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