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 A032727 #11 Aug 13 2024 11:55:47
%S A032727 2,3,6,12,17,23,26,30,33,38,39,45,53,54,57,60,65,68,69,71,72,74,78,81,
%T A032727 87,90,93,96,99,101,105,108,113,114,116,117,126,131,137,141,149,152,
%U A032727 155,156,158,159,164,173,179,183,185,192,203,207,210,212,215,218,222
%N A032727 Numbers k such that k prefixed by '2' and followed by '9' is prime.
%H A032727 Harvey P. Dale, <a href="/A032727/b032727.txt">Table of n, a(n) for n = 1..1000</a>
%t A032727 Select[Range[300],PrimeQ[FromDigits[Join[{2},IntegerDigits[#],{9}]]]&] (* _Harvey P. Dale_, Apr 02 2017 *)
%Y A032727 Cf. A032702-A032733.
%K A032727 nonn,base
%O A032727 1,1
%A A032727 _Patrick De Geest_, May 15 1998