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 A032639 #9 Nov 16 2019 10:29:51 %S A032639 1,7,21,31,49,63,87,111,141,159,189,219,259,267,339,367,391,415,427, %T A032639 463,517,553,601,639,679,717,801,819,855,873,925,991,1039,1087,1117, %U A032639 1147,1275,1303,1323,1387,1417,1471,1519,1563,1611,1659,1675,1711,1857 %N A032639 Lucky numbers indexed by the lucky numbers (Lucky numbers with lucky number subscripts). %H A032639 Amiram Eldar, <a href="/A032639/b032639.txt">Table of n, a(n) for n = 1..10000</a> %F A032639 a(n) = A000959(A000959(n)). - _Amiram Eldar_, Nov 16 2019 %Y A032639 Cf. A000959, A006450. %K A032639 nonn %O A032639 1,2 %A A032639 _Patrick De Geest_, May 15 1998