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A247101 Primes p such that 2*(p^2-1) - 1 and 2*(p^2-1) + 1 are also primes. 2
2, 11, 41, 59, 181, 379, 571, 659, 1429, 1439, 1721, 1879, 2029, 2239, 2351, 2381, 2579, 2671, 3209, 3581, 4159, 4229, 4271, 4969, 4999, 6299, 6451, 6551, 7349, 7841, 10391, 10399, 11059, 11551, 12841, 13049, 13159, 13619, 14071, 15329, 15581, 15889, 16811, 17231, 17749, 18719, 20219 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Subsequence of prime terms of A249446.

LINKS

Table of n, a(n) for n=1..47.

EXAMPLE

2 is in this sequence because 2, 2*(2^2-1) - 1 = 5 and 2*(2^2-1) + 1 = 7 are all primes.

MATHEMATICA

Select[Range[25000], PrimeQ[#] && PrimeQ[2 #^2 - 3] && PrimeQ[2 #^2 - 1] &] (* Vincenzo Librandi, Nov 19 2014 *)

PROG

(MAGMA) [ n: n in [1..22000] | IsPrime(n) and IsPrime(2*(n^2-1)-1) and IsPrime(2*(n^2-1)+1) ];

CROSSREFS

Cf. A249446.

Sequence in context: A290175 A154813 A168367 * A080093 A175447 A078746

Adjacent sequences:  A247098 A247099 A247100 * A247102 A247103 A247104

KEYWORD

nonn

AUTHOR

Juri-Stepan Gerasimov, Nov 18 2014

STATUS

approved

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Last modified October 22 06:02 EDT 2018. Contains 316432 sequences. (Running on oeis4.)