A024632 n written in fractional base 5/2.

0, 1, 2, 3, 4, 20, 21, 22, 23, 24, 40, 41, 42, 43, 44, 210, 211, 212, 213, 214, 230, 231, 232, 233, 234, 400, 401, 402, 403, 404, 420, 421, 422, 423, 424, 440, 441, 442, 443, 444, 2110, 2111, 2112, 2113, 2114, 2130, 2131, 2132, 2133, 2134, 2300, 2301, 2302, 2303

Offset: 0

Author

David W. Wilson

Keywords

• nonn
• base
• easy

Comments

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.

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..10000
• Index entries for sequences related to fractional bases.

Crossrefs

Cf. A245341.

Programs

Maple

a:= proc(n) `if`(n<1, 0, irem(n, 5, 'q')+a(2*q)*10) end:
seq(a(n), n=0..53);  # Alois P. Heinz, May 14 2021

Mathematica

a[n_] := a[n] = If[n == 0, 0, 10 * a[2 * Floor[n/5]] + Mod[n, 5]]; Array[a, 100, 0] (* Amiram Eldar, Jul 30 2025 *)

PARI

a(n) = if(n == 0, 0, 10 * a(n\5 * 2) + n % 5); \\ Amiram Eldar, Jul 30 2025