A037864 a(n)=(number of digits <=2)-(number of digits >2) in base 5 representation of n.

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

Offset: 1

Author

Clark Kimberling

Keywords

• base
• sign

Crossrefs

Cf. A110592.

Programs

Maple

A037864 := proc(n)
    a := 0 ;
    dgs := convert(n,base,5);
    for i from 1 to nops(dgs) do
        if op(i,dgs)<=2 then
            a := a+1 ;
        else
            a := a-1 ;
        end if;
    end do:
    a ;
end proc: # R. J. Mathar, Oct 16 2015

Mathematica

nd5[n_]:=Module[{idn5=IntegerDigits[n,5],a},a=Count[idn5,?(#<=2&)];2a-Length[idn5]]; Array[nd5,90] (* _Harvey P. Dale, Oct 13 2011 *)