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 A249440 #14 Nov 04 2014 16:37:50 %S A249440 0,4,6,13,15,43,47,239,7199,16559,21599,33119,45359,60479,90719, %T A249440 1179359 %N A249440 Positions of records in A249442. %C A249440 a(16) = 1179359 is the largest term less than 7,000,000. %C A249440 From a(8) = 239 onward the decimal representation of all terms seem to end with '9', which indicates that from then on, one larger numbers (A249149) are multiples of ten. %Y A249440 A249439 gives the corresponding record values. %Y A249440 One less than A249149. %Y A249440 Cf. A249442, A249715. %K A249440 nonn,more %O A249440 1,2 %A A249440 _Antti Karttunen_ and _Vladimir Shevelev_, Nov 04 2014