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%I #6 Sep 08 2022 08:46:07
%S 5,7,8,9,11,12,13,14,17,18,20,21,23,25,26,27,29,30,32,33,34,35,36,37,
%T 38,39,40,41,42,43,44,45,47,50,51,52,53,54,55,56,57,58,59,60,62,63,64,
%U 65,67,68,69,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85
%N Numbers n such that prime(n)^2 - 2*n is not prime.
%H Vincenzo Librandi, <a href="/A241028/b241028.txt">Table of n, a(n) for n = 1..5000</a>
%t Select[Range[100], !PrimeQ[Prime[#]^2 - 2 #] &]
%o (Magma) [n: n in [1..100] | not IsPrime(NthPrime(n)^2-2*n)];
%Y Cf. A173473.
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Apr 15 2014
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