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 A309063 #10 Jul 11 2019 15:47:20 %S A309063 1,27,33,39,115,129,141,147,153,159,165,171,177,183,189,195,201,207, %T A309063 213,219,225,231,237,243,249,255,261,267,979,1017,1297,1303,1309,1315, %U A309063 1321,1327,1333,1339,1345,1351,1357,1363,1369,1375,1381,1387,1393,1399,1405 %N A309063 Numbers k such that, when computing A247476(k), all previous terms have been paired. %C A309063 Apparently, the first difference of this sequence is unbounded. %H A309063 Rémy Sigrist, <a href="/A309063/a309063.png">Illustration of first terms</a> %H A309063 Rémy Sigrist, <a href="/A309063/a309063.txt">C program for A309063</a> %e A309063 See illustration of first terms in Links section. %o A309063 (C) See Links section. %Y A309063 Cf. A247476. %K A309063 nonn,base %O A309063 1,2 %A A309063 _Rémy Sigrist_, Jul 10 2019