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A285805
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Prime numbers p such that 6*p-1 and 6*p+1 are composite numbers.
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1
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31, 41, 71, 79, 89, 97, 139, 149, 167, 179, 191, 193, 211, 223, 251, 281, 307, 337, 349, 353, 401, 409, 419, 421, 431, 433, 479, 487, 491, 499, 509, 521, 541, 547, 563, 571, 587, 619, 631, 643, 659, 673, 677, 691, 701, 719, 739, 757, 769, 809
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OFFSET
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1,1
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LINKS
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MAPLE
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filter:= n -> isprime(n) and not isprime(6*n-1) and not isprime(6*n+1):
select(filter, [seq(i, i=3..1000, 2)]); # Robert Israel, Jan 05 2020
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MATHEMATICA
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Select[Prime@Range@150, ! PrimeQ[6 # - 1] && ! PrimeQ[6 # + 1] &] (* Robert G. Wilson v, Apr 27 2017 *)
Select[Prime[Range[150]], NoneTrue[6#+{1, -1}, PrimeQ]&] (* Harvey P. Dale, Jun 10 2022 *)
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PROG
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(PARI) {forprime(n=3, 1000, if(!isprime(6*n-1)&&!isprime(6*n+1), print1(n", ")))}
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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