A037867 a(n)=(number of digits <=3)-(number of digits >3) in base 8 representation of n.

1, 1, 1, -1, -1, -1, -1, 2, 2, 2, 2, 0, 0, 0, 0, 2, 2, 2, 2, 0, 0, 0, 0, 2, 2, 2, 2, 0, 0, 0, 0, 0, 0, 0, 0, -2, -2, -2, -2, 0, 0, 0, 0, -2, -2, -2, -2, 0, 0, 0, 0, -2, -2, -2, -2, 0, 0, 0, 0, -2, -2, -2, -2, 3, 3, 3, 3, 1, 1, 1, 1, 3, 3, 3, 3, 1, 1, 1, 1, 3

Offset

1,8

Links

Table of n, a(n) for n=1..80.

Maple

A037867 := proc(n)
    a := 0 ;
    dgs := convert(n, base, 8);
    for i from 1 to nops(dgs) do
        if op(i, dgs)<=3 then
            a := a+1 ;
        else
            a := a-1 ;
        end if;
    end do:
    a ;
end proc:
seq(A037867(n), n=1..40) ; # R. J. Mathar, Jan 27 2025

Mathematica

d8[n_]:=Module[{idn8=IntegerDigits[n, 8], lt4}, lt4=Count[idn8, _?(#<4&)]; 2lt4-Length[idn8]]; Array[d8, 80] (* Harvey P. Dale, Oct 22 2011 *)

Crossrefs

Sequence in context: A230630 A343957 A338505 * A122879 A037866 A333181

Adjacent sequences: A037864 A037865 A037866 * A037868 A037869 A037870

Keyword

sign,base

Author

Clark Kimberling

Status

approved