This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A049508 #20 Mar 01 2021 07:44:22 %S A049508 2,6,9,14,16,21,23,27,30,38,40,44,48,51,56,61,62,65,71,74,76,84,86,90, %T A049508 96,99,103,108,112,117,119,122,124,130,132,137,143,147,150,153,162, %U A049508 166,170,174,179,183,185,188,191,192,196,198,200,208,213,220,224,227,231 %N A049508 Numbers k such that prime(k) == 3 (mod 10). %C A049508 The asymptotic density of this sequence is 1/4 (by Dirichlet's theorem). - _Amiram Eldar_, Mar 01 2021 %F A049508 a(n) = A000720(A030431(n)). - _Ray Chandler_, Nov 07 2006 %t A049508 Select[Range[240], Mod[Prime[ # ], 10] == 3 &] (* _Ray Chandler_, Nov 07 2006 *) %Y A049508 Cf. A000720, A030431, A102338. %Y A049508 Cf. A049509, A049510, A049511. %K A049508 easy,nonn %O A049508 1,1 %A A049508 _J. Lowell_ %E A049508 Edited and extended by _Ray Chandler_, Nov 07 2006