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%I #26 Sep 08 2022 08:46:10
%S 0,1,2,4,5,54,81,310,360,1117,1410,3320,66162
%N Numbers n such that 57^n + 2 is prime.
%C Numbers of the form 4*h+3 are not in the sequence, since in this case 57^n+2 is divisible by 5.
%C Numbers ending with 6 are not in the sequence, since in this case 57^n+2 is divisible by 11.
%C If n == 10 mod 16, 57^n+2 is divisible by 17. - _Derek Orr_, Oct 04 2014
%C a(14) > 2*10^5. - _Robert Price_, Jun 11 2015
%H Henri & Renaud Lifchitz, <a href="http://www.primenumbers.net/prptop/searchform.php?form=57%5En%2B2&action=Search">PRP Top Records: Search for 57^n+2</a>.
%t Select[Range[0, 2000], PrimeQ[57^# + 2] &]
%o (Magma) [n: n in [0..300]| IsPrime( 57^n + 2 )];
%o (PARI) for(n=1,10^3,if(ispseudoprime(57^n+2),print1(n,", "))) \\ _Derek Orr_, Oct 04 2014
%Y Cf. similar sequences listed in A247957.
%K nonn,more
%O 1,3
%A _Vincenzo Librandi_, Oct 03 2014
%E Edited by _Bruno Berselli_, Oct 04 2014
%E a(13) from _Robert Price_, Jun 11 2015
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