cp's OEIS Frontend

A270039 a(n) = Smallest m >= 7 containing no threes when represented in any base from 4 through n.

%I A270039 #16 Mar 11 2016 05:11:47
%S A270039 8,9,10,32,32,36,64,64,64,64,64,64,64,100,100,100,100,100,100,100,100,
%T A270039 100,104,145,145,145,145,145,145,145,145,145,145
%N A270039 a(n) = Smallest m >= 7 containing no threes when represented in any base from 4 through n.
%C A270039 It remains to be determined if the sequence is finite.
%p A270039 A270039 := proc(n)
%p A270039     local m,nothree,b;
%p A270039     for m from 7 do
%p A270039         nothree := true;
%p A270039         for b from 4 to n do
%p A270039             convert(convert(m,base,b),set) ;
%p A270039             if 3 in % then
%p A270039                 nothree := false;
%p A270039                 break;
%p A270039             fi;
%p A270039         end do:
%p A270039         if nothree then
%p A270039             return m;
%p A270039         end if;
%p A270039     end do:
%p A270039 end proc: # _R. J. Mathar_, Mar 11 2016
%t A270039 Table[SelectFirst[Range[7, 10^3], Total@ Map[Function[k, DigitCount[#, k, 3]], Range[4, n]] == 0 &], {n, 7, 60}] /. n_ /; MissingQ@ n -> Nothing (* _Michael De Vlieger_, Mar 10 2016, Version 10.2 *)
%Y A270039 Cf. A270029, A216192, A270037 - A270045.
%K A270039 nonn,base,more
%O A270039 4,1
%A A270039 _Nathan Fox_, Mar 09 2016