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%I #19 Jan 31 2024 16:28:54
%S 1,10,11,10,101,110,1111111,10,11,1010,10111,110,101,11111110,1111,
%T 100,10001,110,1001,1010,101011111,101110,101001,110,1011111,1010,
%U 1001,11111110,1010011,11110,11111,100,100001,100010,100111111,110
%N Least positive multiple of n written in base 8 using only 0 and 1.
%H Chai Wah Wu, <a href="/A004288/b004288.txt">Table of n, a(n) for n = 0..10000</a>
%p f:= proc(n) local R, S, m, p, Snew, s;
%p R[1]:= 1; R[0]:= 0; S:= {0,1};
%p for m from 1 do
%p p:= 8^m mod n;
%p Snew:= map(s -> s + p mod n, S);
%p if member(0,Snew) then return R[-p mod n]+10^m fi;
%p for s in Snew minus S do R[s] := R[s - p mod n] + 10^m od;
%p S:= S union Snew;
%p od
%p end proc:
%p 1, seq(f(n), n=2..100); # _Robert Israel_, Dec 30 2014
%o (Python)
%o def A004288(n):
%o if n > 0:
%o for i in range(1, 2**n):
%o s = bin(i)[2:]
%o if not int(s,8) % n:
%o return int(s)
%o return 0 # _Chai Wah Wu_, Dec 30 2014
%K nonn,base
%O 1,2
%A _David W. Wilson_
%E a(11), a(22), a(25) corrected by _Chai Wah Wu_, Dec 30 2014
%E Initial 0 deleted and offset corrected by _N. J. A. Sloane_, Jan 31 2024
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