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A173553 Numbers n such that 5+38*n^2 is not a prime. 4

%I #9 Sep 08 2022 08:45:50

%S 5,10,14,15,18,20,25,27,28,30,35,40,41,42,43,44,45,46,47,50,51,52,55,

%T 57,60,65,67,68,69,70,72,73,74,75,76,80,81,85,87,89,90,91,92,94,95,97,

%U 98,100,101,102,103,105,107,109,110,111,112,113,115,117,120,121,124,125,126,127

%N Numbers n such that 5+38*n^2 is not a prime.

%H Vincenzo Librandi, <a href="/A173553/b173553.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Range[150], !PrimeQ[5 + 38 #^2]&] (* _Vincenzo Librandi_, Apr 05 2013 *)

%o (Magma) [n: n in [1..150] | not IsPrime(5 + 38*n^2)]; // _Vincenzo Librandi_, Apr 05 2013

%Y Cf. A173552, A173554, A173555.

%K nonn,easy

%O 1,1

%A _Vincenzo Librandi_, Feb 21 2010

%E Entries recomputed by Alonso Del Arte and _N. J. A. Sloane_, Jun 18 2010

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Last modified April 14 00:20 EDT 2024. Contains 371652 sequences. (Running on oeis4.)