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%I #16 Sep 08 2022 08:44:56
%S 3,5,17,19,31,47,59,61,73,89,101,103,131,157,173,199,227,229,241,257,
%T 269,271,283,311,313,353,367,383,397,409,439,467,479,509,521,523,563,
%U 577,593,607,619,647,661,677,691
%N Primes congruent to {3, 5} mod 7.
%C Primes p such that (1-x^7)/(1-x) is irreducible over GF(p). [_Joerg Arndt_, Aug 10 2011]
%H Vincenzo Librandi, <a href="/A045416/b045416.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Prime[Range[130]],Mod[#,7]==3||Mod[#,7]==5&] (* _Harvey P. Dale_, Jul 15 2011 *)
%o (Magma)[ p: p in PrimesUpTo(1000) | p mod 7 in {3,5} ]; // _Vincenzo Librandi_, Aug 12 2012
%Y Cf. A000040.
%K nonn,easy
%O 1,1
%A _N. J. A. Sloane_