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A244960
Smallest positive multiple of n whose base 9 representation contains only 0's and 1's.
7
1, 10, 9, 820, 10, 90, 91, 5380840, 9, 10, 7381, 7380, 91, 66430, 90, 43644592, 6562, 90, 7372, 820, 819, 65692, 7291, 48427560, 7300, 66430, 81, 532252, 59131, 90, 66340, 48368512, 66429, 6562, 66430, 7380, 532171, 7372, 819, 5380840, 82, 597870, 66349
OFFSET
1,2
LINKS
Ed Pegg Jr., 'Binary' Puzzle
Eric M. Schmidt, Sage code to compute this sequence (use b=9)
Chai Wah Wu, Pigeonholes and repunits, Amer. Math. Monthly, 121 (2014), 529-533.
MATHEMATICA
Module[{nn=15, b9}, b9=Rest[FromDigits[#, 9]&/@Tuples[{0, 1}, nn]]; Table[SelectFirst[ b9, Mod[#, n]==0&], {n, 100}]] (* Harvey P. Dale, Feb 03 2024 *)
PROG
(PARI) a(n, b=9) = if (n, k=1; while(vecmax(digits(k*n, b))>1, k++); k*n); \\ Michel Marcus, Jul 10 2014
CROSSREFS
Cf. A004289 (written in base 9), A004290, A244954-A244959.
Sequence in context: A243035 A070252 A038311 * A282560 A335556 A286775
KEYWORD
nonn,base
AUTHOR
Eric M. Schmidt, Jul 09 2014
EXTENSIONS
Data corrected, offset corrected, and b-file replaced by Harvey P. Dale, Feb 03 2024
STATUS
approved