A043423 Numbers having three 0's in base 8.

512, 1024, 1536, 2048, 2560, 3072, 3584, 4097, 4098, 4099, 4100, 4101, 4102, 4103, 4104, 4112, 4120, 4128, 4136, 4144, 4152, 4160, 4224, 4288, 4352, 4416, 4480, 4544, 4608, 5120, 5632, 6144, 6656, 7168, 7680, 8193, 8194

Offset: 1

Author

Clark Kimberling

Keywords

• nonn
• base

Links

• Robert Israel, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A007094.

Programs

Maple

g:= proc(x) local j; seq(8*x+j,j=1..7) end proc:
h:= x -> 8*x:
B[1,0]:= {$1..7}:
for d from 2 to 5 do
  B[d,0]:= map(g, B[d-1,0]);
  for i from 1 to min(d-2,3) do
    B[d,i]:= map(g, B[d-1,i]) union map(h, B[d-1,i-1])
  od;
  if d <= 4 then B[d,d-1]:= map(h, B[d-1,d-2]) fi;
od:
sort(convert(B[4,3] union B[5,3], list)); # Robert Israel, Jan 15 2019

Mathematica

Select[Range[10000],DigitCount[#,8,0]==3&] (* Harvey P. Dale, Nov 25 2018 *)