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A143827 Numbers n such that 8n^2 - 1 is prime. 8
1, 2, 3, 4, 5, 9, 11, 12, 14, 17, 18, 19, 21, 23, 25, 26, 28, 31, 32, 38, 40, 46, 49, 51, 54, 56, 59, 63, 66, 67, 70, 77, 79, 80, 82, 86, 89, 93, 94, 96, 98, 100, 102, 103, 107, 110, 114, 116, 119, 121, 124, 128, 133, 135, 137, 140, 144, 147, 150, 152, 156, 161, 166 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Contains the even terms of A066049 divided by 2. - R. J. Mathar, Sep 04 2008

LINKS

Table of n, a(n) for n=1..63.

MATHEMATICA

p = 8; a = {}; Do[k = p x^2 - 1; If[PrimeQ[k], AppendTo[a, x]], {x, 1, 1000}]; a

PROG

(PARI) is(n)=isprime(8*n^2-1) \\ Charles R Greathouse IV, Feb 17 2017

CROSSREFS

Cf. A090686, A090684.

Sequence in context: A075177 A062096 A176008 * A100797 A139441 A093305

Adjacent sequences:  A143824 A143825 A143826 * A143828 A143829 A143830

KEYWORD

nonn

AUTHOR

Artur Jasinski, Sep 02 2008

STATUS

approved

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Last modified December 5 15:11 EST 2019. Contains 329753 sequences. (Running on oeis4.)