A163603 - OEIS

%I #16 Mar 01 2021 07:02:55

%S 3,8,15,18,24,27,32,40,50,55,58,65,76,78,85,91,97,99,108,111,123,125,

%T 128,130,135,149,154,158,164,170,180,184,191,194,200,203,207,214,216,

%U 227,229,237,242,246,252,260,266,271

%N Numbers k such that prime(k) == 5 (mod 7).

%C The asymptotic density of this sequence is 1/6 (by Dirichlet's theorem). - _Amiram Eldar_, Mar 01 2021

%H G. C. Greubel, <a href="/A163603/b163603.txt">Table of n, a(n) for n = 1..5000</a>

%F a(n) = A000720(A045458(n)).

%F A000040(a(n)) = A045458(n).

%t Select[Range[300], Mod[Prime[#], 7] == 5 &] (* _G. C. Greubel_, Jul 29 2017 *)

%o (PARI) isok(n) = (prime(n) % 7) == 5; \\ _Michel Marcus_, Jul 29 2017

%Y Cf. A000040, A000720, A045458.

%K nonn

%O 1,1

%A _Juri-Stepan Gerasimov_, Aug 01 2009

%E Remainder in definition corrected by _R. J. Mathar_, Aug 01 2009