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URL: https://oeis.org/A125272

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A125272
Primes p such that 3p - 2 and 3p + 2 are also primes.
18
3, 5, 7, 13, 23, 37, 43, 103, 127, 163, 167, 257, 293, 313, 337, 433, 523, 757, 797, 887, 953, 1013, 1063, 1153, 1283, 1303, 1307, 1483, 1597, 1657, 1667, 1693, 1723, 1783, 1913, 2003, 2333, 2347, 2557, 2897, 2927, 3067, 3533, 3823, 3943, 4003, 4013, 4093
OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = A125215(n)/3.
MATHEMATICA
lst={}; Do[p=Prime[n]; If[PrimeQ[3*p-2]&&PrimeQ[3*p+2], AppendTo[lst, p]], {n, 7!}]; lst (* Vladimir Joseph Stephan Orlovsky, Jan 18 2009 *)
Select[Prime[Range[600]], AllTrue[3#+{2, -2}, PrimeQ]&] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 29 2021 *)
PROG
(Magma) [p: p in PrimesUpTo(70000)| IsPrime(3*p-2)and IsPrime(3*p+2)]; // Vincenzo Librandi, Jan 29 2011
(PARI) is(n)=isprime(3*n-2)&&isprime(3*n+2)&&isprime(n) \\ Charles R Greathouse IV, Jul 02 2013
CROSSREFS
Intersection of A023208 and A088878.
Cf. A125215.
Sequence in context: A321671 A085013 A164939 * A127443 A003229 A077949
KEYWORD
nonn,easy
AUTHOR
Zak Seidov, Nov 26 2006
STATUS
approved