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A352804
a(n) = A028876(n)/2; numbers k such that 4*k^2 - 5 is prime.
2
2, 3, 4, 6, 7, 8, 11, 12, 16, 17, 18, 19, 21, 22, 23, 26, 29, 32, 36, 37, 39, 41, 47, 51, 56, 58, 61, 66, 72, 76, 82, 83, 84, 87, 88, 91, 92, 93, 94, 99, 102, 106, 111, 113, 116, 117, 118, 126, 131, 132, 139, 142, 144, 146, 149, 151, 159, 162, 171, 177, 179
OFFSET
1,1
COMMENTS
A028876 with common factor 2 removed.
LINKS
MATHEMATICA
Select[Range[200], PrimeQ[4*#^2 - 5] &]
PROG
(PARI) isA352804(n)=isprime(4*n^2-5)
CROSSREFS
Cf. A028876, A028877 (the resulting primes), A352805.
Sequence in context: A274281 A050116 A061985 * A102826 A191381 A051602
KEYWORD
nonn,easy
AUTHOR
Jianing Song, Apr 04 2022
STATUS
approved