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A174357 Primes p such that 2*p^2+-9 are also prime. 1
5, 7, 11, 17, 31, 61, 79, 101, 137, 163, 193, 227, 311, 401, 509, 521, 641, 653, 1019, 1151, 1201, 1229, 1279, 1433, 1459, 1523, 1559, 1601, 1669, 1999, 2053, 2153, 2203, 2207, 2357, 3061, 3643, 3671, 4127, 4447, 4603, 5099, 5507, 5651, 5701, 5813, 6079 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
EXAMPLE
For p=5, 2*5^2-+9=(41,59); p=7, 2*7^2-+9=(89,107); p=11, 2*11^2-+9=(233,251)
MATHEMATICA
Select[Prime[Range[100]], PrimeQ[2 #^2 - 9]&&PrimeQ[2 #^2 + 9]&] (* Vincenzo Librandi, Apr 10 2013 *)
PROG
(Magma) [p: p in PrimesUpTo(10000)|IsPrime(2*p^2-9) and IsPrime(2*p^2+9)]
CROSSREFS
Sequence in context: A060449 A046140 A023241 * A134572 A106954 A027755
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Mar 17 2010
STATUS
approved

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Last modified July 20 18:43 EDT 2024. Contains 374459 sequences. (Running on oeis4.)