A244955 Smallest positive multiple of n whose base-4 representation contains only 0's and 1's.
1, 4, 21, 4, 5, 84, 21, 16, 81, 20, 341, 84, 65, 84, 1365, 16, 17, 324, 1045, 20, 21, 1364, 69, 336, 325, 260, 81, 84, 261, 5460, 341, 64, 1089, 68, 1365, 324, 4181, 4180, 273, 80, 1025, 84, 5461, 1364, 5445, 276, 20821, 336, 1029, 1300, 4437, 260, 5141
Offset: 1
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
- Ed Pegg Jr., 'Binary' Puzzle
- Eric M. Schmidt, Sage code to compute this sequence (use b=4)
- Chai Wah Wu, Pigeonholes and repunits, Amer. Math. Monthly, 121 (2014), 529-533.
Programs
-
Mathematica
Module[{nn=10,b4},b4=Rest[FromDigits[#,4]&/@Tuples[{0,1},nn]];Table[SelectFirst[b4,Mod[ #,n]==0&],{n,60}]] (* Harvey P. Dale, Feb 01 2024 *)
Extensions
Data corrected, offset corrected, and b-file replaced by Harvey P. Dale, Feb 01 2024