login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Numbers k such that prime(k) == 7 (mod 10).
6

%I #18 Mar 01 2021 07:44:38

%S 4,7,12,15,19,25,28,31,33,37,39,45,49,55,59,63,66,68,69,73,78,88,91,

%T 93,101,102,106,107,111,113,118,123,129,134,138,139,144,148,151,154,

%U 155,159,161,163,165,168,181,184,187,195,199,203,206,211,214,217,219,225

%N Numbers k such that prime(k) == 7 (mod 10).

%C The asymptotic density of this sequence is 1/4 (by Dirichlet's theorem). - _Amiram Eldar_, Mar 01 2021

%F a(n) = A000720(A030432(n)). - _Ray Chandler_, Nov 07 2006

%t Select[Range[240], Mod[Prime[ # ], 10] == 7 &] (* _Ray Chandler_, Nov 07 2006 *)

%Y Cf. A000720, A030432, A102342.

%Y Cf. A049508, A049510, A049511.

%K nonn

%O 1,1

%A _N. J. A. Sloane_

%E Extended by _Ray Chandler_, Nov 07 2006