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 A024650 #11 Aug 02 2025 06:26:06 %S A024650 0,1,2,3,4,5,6,7,8,20,21,22,23,24,25,26,27,28,40,41,42,43,44,45,46,47, %T A024650 48,60,61,62,63,64,65,66,67,68,80,81,82,83,84,85,86,87,88,210,211,212, %U A024650 213,214,215,216,217,218,230,231,232,233,234,235,236,237,238,250,251,252,253 %N A024650 n written in fractional base 9/2. %C A024650 To represent a number in base b, if a digit exceeds b-1, subtract b and carry 1. In fractional base a/b, subtract a and carry b. %H A024650 Amiram Eldar, <a href="/A024650/b024650.txt">Table of n, a(n) for n = 0..10000</a> %H A024650 <a href="/index/Ba#base_fractional">Index entries for sequences related to fractional bases</a>. %t A024650 a[n_] := a[n] = If[n == 0, 0, 10 * a[2 * Floor[n/9]] + Mod[n, 9]]; Array[a, 50, 0] (* _Amiram Eldar_, Aug 02 2025 *) %o A024650 (PARI) a(n) = if(n == 0, 0, 10 * a(n\9 * 2) + n % 9); \\ _Amiram Eldar_, Aug 02 2025 %Y A024650 Cf. A245345. %K A024650 nonn,base,easy %O A024650 0,3 %A A024650 _David W. Wilson_