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%I #14 Sep 08 2022 08:46:09
%S 2,11,41,59,181,379,571,659,1429,1439,1721,1879,2029,2239,2351,2381,
%T 2579,2671,3209,3581,4159,4229,4271,4969,4999,6299,6451,6551,7349,
%U 7841,10391,10399,11059,11551,12841,13049,13159,13619,14071,15329,15581,15889,16811,17231,17749,18719,20219
%N Primes p such that 2*(p^2-1) - 1 and 2*(p^2-1) + 1 are also primes.
%C Subsequence of prime terms of A249446.
%e 2 is in this sequence because 2, 2*(2^2-1) - 1 = 5 and 2*(2^2-1) + 1 = 7 are all primes.
%t Select[Range[25000], PrimeQ[#] && PrimeQ[2 #^2 - 3] && PrimeQ[2 #^2 - 1] &] (* _Vincenzo Librandi_, Nov 19 2014 *)
%o (Magma) [ n: n in [1..22000] | IsPrime(n) and IsPrime(2*(n^2-1)-1) and IsPrime(2*(n^2-1)+1) ];
%Y Cf. A249446.
%K nonn
%O 1,1
%A _Juri-Stepan Gerasimov_, Nov 18 2014