A093012 - OEIS

%I #22 Sep 08 2022 08:45:13

%S 2,8,19,23,32,38,41,47,49,63,81,91,95,101,103,117,120,125,131,138,153,

%T 161,182,188,193,195,208,225,232,241,248,256,262,266,272,280,292,300,

%U 304,314,317,321,327,334,346,351,365,370,376,385,394,409,410,414,427

%N Numbers k such that prime(k) == 3 (mod 16).

%C A091968 indexed by A000040.

%C The asymptotic density of this sequence is 1/8 (by Dirichlet's theorem). - _Amiram Eldar_, Mar 01 2021

%H G. C. Greubel, <a href="/A093012/b093012.txt">Table of n, a(n) for n = 1..5000</a>

%F A000040(a(n)) = A091968(n).

%F a(n) = A000720(A091968(n)).

%t Select[Range[430], Mod[Prime[ # ], 16] == 3 &] (* _Ray Chandler_, Nov 06 2006 *)

%o (Magma) [n: n in [1..450]|(NthPrime(n) mod 16) eq 3] // _G. C. Greubel_, Feb 05 2019

%o (PARI) {isok(n) = Mod(prime(n), 16)==3};

%o for(n=1, 450, if(isok(n)==1, print1(n, ", "), 0)) \\ _G. C. Greubel_, Feb 05 2019

%Y Cf. A000040, A000720, A091968, A092022.

%K nonn

%O 1,1

%A _Ray Chandler_, Mar 15 2004, revised Nov 06 2006