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A288246 Numbers k such that 8*k^3 + 81 is prime. 1

%I

%S 1,4,8,10,11,13,20,26,29,34,35,43,46,50,53,56,68,70,71,85,86,94,95,98,

%T 125,130,131,139,149,154,160,161,163,169,170,178,184,194,196,199,208,

%U 215,229,239,259,266,269,271,280,283,286,290,298,305,313

%N Numbers k such that 8*k^3 + 81 is prime.

%H Vincenzo Librandi, <a href="/A288246/b288246.txt">Table of n, a(n) for n = 1..4400</a>

%e a(1) = 1 because 8*1 + 81 = 89 is prime.

%e a(2) = 4 because 8*4^3 + 81 = 593 is prime.

%t Select[Range[500], PrimeQ[8 #^3 + 81] &]

%o (MAGMA) [n: n in [0..500] |IsPrime(8*n^3+81)];

%Y Cf. A155722: Numbers k such that 2*k + 9 is prime.

%Y Cf. A002971: Numbers k such that 4*k^2 + 25 is prime.

%K nonn,easy

%O 1,2

%A _Vincenzo Librandi_, Jun 07 2017

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Last modified October 26 18:30 EDT 2021. Contains 348268 sequences. (Running on oeis4.)