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A245056
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Primes in the sequence A249134/12.
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2
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2, 109, 157, 167, 197, 211, 227, 317, 337, 349, 353, 389, 421, 439, 449, 457, 521, 541, 547, 563, 571, 587, 599, 613, 617, 647, 677, 701, 733, 757, 769, 821, 823, 827, 857, 859, 877, 881, 967, 977, 983, 991, 1097, 1153, 1163, 1187, 1217, 1231, 1237, 1249
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OFFSET
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1,1
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COMMENTS
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a(n) is in the sequence if Bernoulli number B(12*a(n)) has denominator 2730 and a(n) is prime.
2 together with primes p such that 2p+1, 4p+1, 6p+1, and 12p+1 are all composite. - Charles R Greathouse IV, Oct 22 2014
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LINKS
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FORMULA
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MATHEMATICA
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Reap[For[n = 0, n <= 10^4, n = n + 12, If[Denominator[BernoulliB[n]] == 2730 && PrimeQ[n/12], Print[n/12]; Sow[n/12]]]][[2, 1]]
Flatten[{2, Select[Table[Prime[k], {k, 300}], Not[PrimeQ[2*# + 1]] && Not[PrimeQ[4*# + 1]] && Not[PrimeQ[6*# + 1]] && Not[PrimeQ[12*# + 1]] &]}] (* Vaclav Kotesovec, Aug 03 2019 *)
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PROG
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(PARI) is(n)=n==2 || (isprime(n) && !isprime(2*n+1) && !isprime(4*n+1) && !isprime(6*n+1) && !isprime(12*n+1)) \\ Charles R Greathouse IV, Oct 22 2014
(Magma) [2] cat [n: n in [0..1500] | IsPrime(n) and not IsPrime(2*n+1) and not IsPrime(4*n+1) and not IsPrime(6*n+1) and not IsPrime(12*n+1)]; // Vincenzo Librandi, Oct 23 2014
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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