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 A050737 #5 Oct 16 2019 01:13:00 %S A050737 1,7,49,343,2401,16807,823543,5764801,40353607,282475249,13841287201, %T A050737 232630513987207,65712362363534280139543 %N A050737 Numbers of form 7^k (values of k see A050728) containing no pair of consecutive equal digits (probably finite). %Y A050737 Cf. A043096, A050728. %K A050737 nonn,base %O A050737 0,2 %A A050737 _Patrick De Geest_, Sep 15 1999