A120222 - OEIS

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A120222

Numbers k such that 6+k and 6*k+1 are prime.

1, 5, 7, 11, 13, 17, 23, 25, 35, 37, 47, 55, 61, 73, 77, 83, 91, 95, 101, 103, 107, 121, 125, 131, 143, 151, 161, 173, 175, 187, 205, 217, 221, 233, 245, 257, 263, 271, 277, 287, 305, 311, 325, 331, 347, 367, 373, 391, 395, 425, 443, 451, 455, 461, 481, 503, 551

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OFFSET

1,2

COMMENTS

All terms == 1 or 5 (mod 6). - Robert Israel, Oct 29 2020

LINKS

Robert Israel, Table of n, a(n) for n = 1..10000

MAPLE

select(n -> isprime(n+6) and isprime(6*n+1), [seq(i, i=1..1000, 2)]); # Robert Israel, Oct 29 2020

MATHEMATICA

Select[Range[551], PrimeQ[#+6]&&PrimeQ[6#+1]&] (* James C. McMahon, Sep 26 2024 *)

CROSSREFS