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A269704 Numbers k such that prime(k) == 1 (mod 8).

%I A269704 #18 Sep 08 2022 08:46:15
%S A269704 7,13,21,24,25,30,33,44,51,53,55,60,65,68,71,79,80,84,87,88,98,104,
%T A269704 106,108,110,113,116,122,135,136,140,148,152,158,159,162,165,169,174,
%U A269704 176,184,189,191,196,197,199,204,209,211,216,218,223,227,234,237,245
%N A269704 Numbers k such that prime(k) == 1 (mod 8).
%C A269704 The asymptotic density of this sequence is 1/4 (by Dirichlet's theorem). - _Amiram Eldar_, Mar 01 2021
%H A269704 Robert Israel, <a href="/A269704/b269704.txt">Table of n, a(n) for n = 1..10000</a>
%e A269704 a(1) = 7 because prime(7) = 17 and 17 == 1 (mod 8).
%p A269704 Res:= NULL: count:= 0:
%p A269704 p:= 2:
%p A269704 for n from 2 while count < 100 do
%p A269704   p:= nextprime(p);
%p A269704   if p mod 8 = 1 then count:= count+1; Res:= Res, n fi
%p A269704 od:
%p A269704 Res; # _Robert Israel_, May 06 2019
%t A269704 Select[Range[300], Mod[Prime[#], 8] == 1 &]
%o A269704 (Magma) [n: n in [1..500] | NthPrime(n) mod 8 eq 1];
%o A269704 (PARI) lista(nn) = for(n=1, nn, if(Mod(prime(n),8)==1, print1(n, ", "))); \\ _Altug Alkan_, Mar 04 2016
%Y A269704 The associated primes are in A007519.
%Y A269704 Cf. similar sequences listed in A269703.
%K A269704 nonn
%O A269704 1,1
%A A269704 _Vincenzo Librandi_, Mar 04 2016