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%I #30 Sep 08 2022 08:45:02
%S 2,19,79,331,439,499,619,829,1069,1279,1531,2089,2131,2179,2311,2791,
%T 3019,3061,3109,3181,3769,4159,4231,4261,4621,4639,4861,4951,5419,
%U 5749,6121,6211,6709,6841,7369,7411,7561,7639,8209,8629,9109,9199,9319,9739,10321,10831
%N First member of a prime triple in a 2p-1 progression.
%C Numbers n such that n remains prime through 2 iterations of function f(x) = 2x - 1.
%H Vincenzo Librandi, <a href="/A057326/b057326.txt">Table of n, a(n) for n = 1..2100</a>
%H <a href="/index/Pri#primes_AP">Index entries for sequences related to primes in arithmetic progressions</a>
%e Triplets are (2,3,5), (19,37,73), (79,157,313), (331,661,1321), ...
%p select(p -> andmap(isprime,[p, 2*p-1, 4*p-3]), [seq(p, p=0..10000)]); # _K. D. Bajpai_, Jun 26 2017
%t Select[Prime[Range[1500]],And@@PrimeQ[NestList[2#-1&,#,2]]&] (* _Harvey P. Dale_, Dec 09 2011 *)
%o (PARI) forprime(p= 1, 100000, if(isprime(2*p-1) && isprime(4*p-3), print1(p, ", "))); \\ _K. D. Bajpai_, Jun 26 2017
%o (Magma) [p: p in PrimesUpTo (10000) | IsPrime(2*p-1) and IsPrime(4*p-3)]; // _K. D. Bajpai_, Jun 26 2017
%Y Cf. (A005382 and A005383), A057327, A057328, A057329, A057330, A005603.
%K nonn
%O 1,1
%A _Patrick De Geest_, Aug 15 2000
%E Offset set to 1 by _Michel Marcus_, Jul 02 2017
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