A024641 n written in fractional base 7/4.

0, 1, 2, 3, 4, 5, 6, 40, 41, 42, 43, 44, 45, 46, 410, 411, 412, 413, 414, 415, 416, 450, 451, 452, 453, 454, 455, 456, 4120, 4121, 4122, 4123, 4124, 4125, 4126, 4160, 4161, 4162, 4163, 4164, 4165, 4166, 4530, 4531, 4532, 4533, 4534, 4535, 4536, 41200, 41201

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

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

Crossrefs

Cf. A245349.

Programs

Mathematica

a[n_] := a[n] = If[n == 0, 0, 10 * a[4 * Floor[n/7]] + Mod[n, 7]]; Array[a, 50, 0] (* Amiram Eldar, Jul 31 2025 *)

PARI

a(n) = if(n == 0, 0, 10 * a(n\7 * 4) + n % 7); \\ Amiram Eldar, Jul 31 2025