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 A025685 #13 Feb 26 2024 15:24:31 %S A025685 0,0,0,1,0,1,0,1,2,0,1,2,0,1,2,3,0,1,2,3,0,1,2,3,4,0,1,2,3,4,0,1,2,3, %T A025685 4,5,0,1,2,3,4,5,0,1,2,3,4,5,6,0,1,2,3,4,5,6,0,1,2,3,4,5,6,7,0,1,2,3, %U A025685 4,5,6,7,0,1,2,3,4,5,6,7,8,0,1,2,3,4,5,6,7,8,0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7 %N A025685 Exponent of 10 (value of j) in n-th number of form 3^i*10^j. %C A025685 Different from A055087, since a(143)=0 and a(144)=11. %F A025685 a(n) = A007814(A025616(n)). - _R. J. Mathar_, Feb 26 2024 %Y A025685 Cf. A007814, A025616, A055087. %K A025685 nonn %O A025685 1,9 %A A025685 _David W. Wilson_