A098160 Numbers n with property that when writing down all the natural numbers from 0 to n one uses the same number of even and odd digits.

1, 3, 5, 7, 9, 10, 28, 29, 30, 48, 49, 50, 68, 69, 70, 88, 89, 90

Offset

1,2

Comments

The sequence seems to stop at 90.

Links

Table of n, a(n) for n=1..18.

Example

[0,1,2,3,4,5,6,7,8,9,10] uses 6 even digits and 6 odd digits.

Mathematica

f[n_] := Block[{id = Mod[ Flatten[ Table[ IntegerDigits[i], {i, 0, n}]], 2]}, Length[id] - 2Plus @@ id]; Select[ Range[ 100], f[ # ] == 0 &] (* Robert G. Wilson v, Nov 03 2004 *)
sneoQ[n_]:=Module[{d=Flatten[IntegerDigits/@Range[0, n]]}, 2*Count[ d, _?OddQ] == Length[d]]; Select[Range[100], sneoQ] (* Harvey P. Dale, Jul 31 2017 *)

Crossrefs

Sequence in context: A066929 A173909 A165249 * A371215 A103701 A206544

Adjacent sequences: A098157 A098158 A098159 * A098161 A098162 A098163

Keyword

base,easy,nonn,fini,full

Author

Eric Angelini, Oct 25 2004

Status

approved