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 A025686 #10 Jul 06 2025 12:40:56 %S A025686 0,0,1,0,1,0,2,1,0,2,1,3,0,2,1,3,0,2,4,1,3,0,2,4,1,3,0,5,2,4,1,3,0,5, %T A025686 2,4,1,6,3,0,5,2,4,1,6,3,0,5,2,7,4,1,6,3,0,5,2,7,4,1,6,3,0,8,5,2,7,4, %U A025686 1,6,3,0,8,5,2,7,4,1,9,6,3,0,8,5,2,7,4,1,9,6,3,0,8,5,2,10,7,4,1,9,6,3,0,8,5,2,10 %N A025686 Exponent of 10 (value of j) in n-th number of form 4^i*10^j. %Y A025686 Cf. A025621. Differs from A025657 at a(114). A025649 is the exponent of 4. %K A025686 nonn %O A025686 1,7 %A A025686 _David W. Wilson_