A024652 - OEIS

%I #11 Aug 02 2025 06:26:09

%S 0,1,2,3,4,5,6,7,8,40,41,42,43,44,45,46,47,48,80,81,82,83,84,85,86,87,

%T 88,430,431,432,433,434,435,436,437,438,470,471,472,473,474,475,476,

%U 477,478,820,821,822,823,824,825,826,827,828,860,861,862,863,864,865,866,867,868

%N n written in fractional base 9/4.

%C 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 Amiram Eldar, <a href="/A024652/b024652.txt">Table of n, a(n) for n = 0..10000</a>

%H <a href="/index/Ba#base_fractional">Index entries for sequences related to fractional bases</a>.

%t a[n_] := a[n] = If[n == 0, 0, 10 * a[4 * Floor[n/9]] + Mod[n, 9]]; Array[a, 50, 0] (* _Amiram Eldar_, Aug 02 2025 *)

%o (PARI) a(n) = if(n == 0, 0, 10 * a(n\9 * 4) + n % 9); \\ _Amiram Eldar_, Aug 02 2025

%Y Cf. A245350.

%K nonn,base,easy

%O 0,3

%A _David W. Wilson_