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Primes p such that m - p#/6 or p#/6 - n is not in A002822 (twin ranks), where m (resp. n) is the next larger (resp. smaller) twin rank w.r.t. p#/6, and # = A034386 (primorial).
0

%I #12 May 23 2021 02:49:35

%S 41,227,307,311,349,457,613

%N Primes p such that m - p#/6 or p#/6 - n is not in A002822 (twin ranks), where m (resp. n) is the next larger (resp. smaller) twin rank w.r.t. p#/6, and # = A034386 (primorial).

%C Related to the "Twin Fortune Conjecture" (A. Dinculescu) which states that the distance between p#/6 and the next larger or smaller n in A002822 (twin rank, such that 6n +- 1 are twin primes) is again a twin rank; very similar to Fortune's Conjecture, cf. A005235.

%C For a(1) = 41, the non twin rank is p#/6 - n, for all other terms listed here, it is m - p#/6. However, in these cases, the other distance is a twin rank. For all other primes, both distances are twin ranks.

%o (PARI) is(p)={ my(m=A034386(p)/6,n=m); until(is_A002822(n-=1),); (is_A002822(m-n) || ((n=m) && !until(is_A002822(m+=1),) && is_A002822(m-n))) && isprime(p)}

%Y Cf. A002822 (twin ranks), A034386 (primorial), A005235 (Fortunate numbers).

%K nonn,hard,more

%O 1,1

%A _M. F. Hasler_, Jun 24 2019

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