A352804 a(n) = A028876(n)/2; numbers k such that 4*k^2 - 5 is prime.

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

Jianing Song, Table of n, a(n) for n = 1..10000

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 A378171

Adjacent sequences: A352801 A352802 A352803 * A352805 A352806 A352807

Keyword

nonn,easy

Author

Jianing Song, Apr 04 2022

Status

approved