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 A025649 #10 Jul 06 2025 14:03:48 %S A025649 0,1,0,2,1,3,0,2,4,1,3,0,5,2,4,1,6,3,0,5,2,7,4,1,6,3,8,0,5,2,7,4,9,1, %T A025649 6,3,8,0,5,10,2,7,4,9,1,6,11,3,8,0,5,10,2,7,12,4,9,1,6,11,3,8,13,0,5, %U A025649 10,2,7,12,4,9,14,1,6,11,3,8,13,0,5,10,15,2,7,12,4,9,14,1,6,11,16,3,8,13,0,5,10 %N A025649 Exponent of 4 (value of i) in n-th number of form 4^i*10^j. %Y A025649 Cf. A025621. Differs from A025641 at a(114). A025686 is exponent of 10. %K A025649 nonn %O A025649 1,4 %A A025649 _David W. Wilson_