Quote:
Originally Posted by sweety439
This page is only for the twin case and the Riesel case, for the Sierpinski case, see http://harvey563.tripod.com/cunninghams.txt
An interesting one is k=279, there is no known twin prime (k*2^n1 and k*2^n+1), neither known 1st kind SophieGermain prime/Cunningham chain (k*2^n1 and k*2^(n+1)1) or known 2nd kind SophieGermain prime/Cunningham chain (k*2^n+1 and k*2^(n+1)+1)
Twin prime: CK=237
1st kind SophieGermain prime/Cunningham chain: CK=807
2nd kind SophieGermain prime/Cunningham chain: CK=32469

There is no known twin prime for some
even k divisible by 3, e.g. k=312 (since all n must be >=1)