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 A031888 #8 Nov 15 2019 06:28:30 %S A031888 15,25,37,43,87,93,99,105,135,163,195,205,261,267,297,321,361,385,393, %T A031888 409,415,421,477,489,511,529,553,645,673,679,693,717,729,781,867,897, %U A031888 1023,1087,1095,1117,1183,1203,1275,1285,1303,1323,1389 %N A031888 Lucky numbers with size of gaps equal to 6 (lower terms). %H A031888 Amiram Eldar, <a href="/A031888/b031888.txt">Table of n, a(n) for n = 1..10000</a> %Y A031888 Cf. A000959. %K A031888 nonn %O A031888 1,1 %A A031888 _Patrick De Geest_