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 A024642 #14 Jul 31 2025 03:51:32 %S A024642 0,1,2,3,4,5,6,50,51,52,53,54,55,56,530,531,532,533,534,535,536,5310, %T A024642 5311,5312,5313,5314,5315,5316,5360,5361,5362,5363,5364,5365,5366, %U A024642 53140,53141,53142,53143,53144,53145,53146,53620,53621,53622,53623,53624,53625 %N A024642 n written in fractional base 7/5. %C A024642 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 A024642 Amiram Eldar, <a href="/A024642/b024642.txt">Table of n, a(n) for n = 0..10000</a> %H A024642 <a href="/index/Ba#base_fractional">Index entries for sequences related to fractional bases</a>. %t A024642 a[n_] := a[n] = If[n == 0, 0, 10 * a[5 * Floor[n/7]] + Mod[n, 7]]; Array[a, 50, 0] (* _Amiram Eldar_, Jul 31 2025 *) %o A024642 (PARI) a(n) = if(n == 0, 0, 10 * a(n\7 * 5) + n % 7); \\ _Amiram Eldar_, Jul 31 2025 %Y A024642 Cf. A245352. %K A024642 nonn,base,easy %O A024642 0,3 %A A024642 _David W. Wilson_