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Primes congruent to {0, 5} mod 7.
1

%I #12 Sep 08 2022 08:44:56

%S 5,7,19,47,61,89,103,131,173,229,257,271,313,383,397,439,467,509,523,

%T 593,607,677,691,719,733,761,859,887,929,971,1013,1069,1097,1153,1181,

%U 1223,1237,1279,1307,1321,1433

%N Primes congruent to {0, 5} mod 7.

%C Because 7 is the only prime congruent to 0 mod 7, it is more efficient to search only for primes that are congruent to 5 mod 7 and then insert 7 as the second term of the sequence (see the second Mathematica program below). - _Harvey P. Dale_, Jun 24 2017

%H Vincenzo Librandi, <a href="/A045447/b045447.txt">Table of n, a(n) for n = 1..1000</a>

%t Select[Prime[Range[200]],MemberQ[{0,5},Mod[#,7]]&] (* _Vincenzo Librandi_, Aug 13 2012 *)

%t Insert[Select[Prime[Range[500]],Mod[#,7]==5&],7,2] (* _Harvey P. Dale_, Jun 24 2017 *)

%o (Magma) [ p: p in PrimesUpTo(2000) | p mod 7 in {0, 5} ]; // _Vincenzo Librandi_, Aug 13 2012

%Y Cf. A000040.

%K nonn,easy

%O 1,1

%A _N. J. A. Sloane_