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 A028901 #7 Jul 08 2025 18:55:01 %S A028901 0,1,2,3,4,5,6,7,8,9,6,7,8,9,10,11,12,13,14,15,12,13,14,15,16,17,18, %T A028901 19,20,21,18,19,20,21,22,23,24,25,26,27,24,25,26,27,28,29,30,31,32,33, %U A028901 30,31,32,33,34,35,36,37,38,39,36,37,38,39,40,41,42,43,44,45,42,43,44,45 %N A028901 Map n = Sum c_i 10^i to a(n) = Sum c_i 6^i. %K A028901 nonn,base %O A028901 0,3 %A A028901 _N. J. A. Sloane_ %E A028901 More terms from _Erich Friedman_.