

A187563


Least k >=0 and k < prime(n) such that prime(n)*(prime(n)k)1 and prime(n)*(prime(n)k)+1 are twin primes or 1 if no such k exists.


2



0, 1, 1, 1, 1, 1, 11, 7, 17, 11, 1, 1, 11, 13, 41, 1, 41, 1, 1, 11, 1, 1, 17, 41, 1, 23, 97, 11, 7, 47, 1, 59, 71, 1, 137, 31, 97, 67, 137, 119, 47, 43, 101, 7, 101, 91, 43, 13, 11, 31, 137, 71, 49, 41, 137, 47, 11, 61, 67
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OFFSET

1,7


COMMENTS

Conjectures: there are only 11 primes (5,11,13,31,37,53,61,73,79,97,127) for which k does not exist and there is always at least a pair of twin primes between prime(n) and prime(n)^2.


LINKS



MATHEMATICA

Table[k = 0; While[k < Prime[n] && ! (PrimeQ[Prime[n]*(Prime[n]  k)  1] && PrimeQ[Prime[n]*(Prime[n]  k) + 1]), k++]; If[k == Prime[n], k = 1]; k, {n, 100}]


CROSSREFS



KEYWORD

sign


AUTHOR



STATUS

approved



