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 A032666 #9 Sep 03 2017 03:21:01 %S A032666 1,7,11,13,17,31,37,47,49,53,59,67,73,79,83,89,97,109,119,121,137,163, %T A032666 167,169,181,187,191,203,209,217,221,229,251,253,257,259,271,299,301, %U A032666 307,313,319,323,329,331,343,347,359,361,371,373,389,391 %N A032666 Digit '3' concatenated with a(n) is a prime. %H A032666 Seiichi Manyama, <a href="/A032666/b032666.txt">Table of n, a(n) for n = 1..10000</a> %K A032666 nonn,base %O A032666 1,2 %A A032666 _Patrick De Geest_, May 15 1998 %E A032666 Edited by _Charles R Greathouse IV_, Aug 02 2010