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

8, 9, 10, 32, 32, 36, 64, 64, 64, 64, 64, 64, 64, 100, 100, 100, 100, 100, 100, 100, 100, 100, 104, 145, 145, 145, 145, 145, 145, 145, 145, 145, 145

Offset

4,1

Comments

It remains to be determined if the sequence is finite.

Links

Table of n, a(n) for n=4..36.

Maple

A270039 := proc(n)
    local m, nothree, b;
    for m from 7 do
        nothree := true;
        for b from 4 to n do
            convert(convert(m, base, b), set) ;
            if 3 in % then
                nothree := false;
                break;
            fi;
        end do:
        if nothree then
            return m;
        end if;
    end do:
end proc: # R. J. Mathar, Mar 11 2016

Mathematica

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 *)

Crossrefs

Cf. A270029, A216192, A270037 - A270045.

Sequence in context: A343860 A308809 A272142 * A048020 A363760 A048000

Adjacent sequences: A270036 A270037 A270038 * A270040 A270041 A270042

Keyword

nonn,base,more

Author

Nathan Fox, Mar 09 2016

Status

approved