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 A031902 #7 Nov 16 2019 03:28:27 %S A031902 937,1777,2923,2983,3007,3133,3727,4207,4675,4741,5191,5527,5617,6601, %T A031902 7609,7717,8233,8515,9895,9937,10153,10291,10321,11137,12337,12499, %U A031902 12679,13657,13873,14755,14797,14977,15271,15313,15397,15547 %N A031902 Lucky numbers with size of gaps equal to 20 (lower terms). %H A031902 Amiram Eldar, <a href="/A031902/b031902.txt">Table of n, a(n) for n = 1..10000</a> %Y A031902 Cf. A000959, A031903. %K A031902 nonn %O A031902 1,1 %A A031902 _Patrick De Geest_