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 A039434 #11 Jun 30 2021 03:57:56 %S A039434 69,96,169,196,269,296,369,396,469,496,569,596,609,619,629,639,649, %T A039434 659,679,689,690,691,692,693,694,695,697,698,769,796,869,896,906,916, %U A039434 926,936,946,956,960,961,962,963,964,965,967,968,976,986,1069,1096 %N A039434 Numbers whose base-10 representation has the same nonzero number of 6's and 9's. %K A039434 nonn,base,easy %O A039434 1,1 %A A039434 _Olivier Gérard_