A007957 Numbers that contain an odd digit.

1, 3, 5, 7, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 23, 25, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 41, 43, 45, 47, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 61, 63, 65, 67, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 81, 83, 85, 87, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100

Offset: 1

Author

R. Muller

Keywords

• nonn
• base
• easy

Comments

Complement of A014263; A196564(a(n)) > 0; A103181(a(n)) > 0. - Reinhard Zumkeller, Oct 04 2011

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
• F. Smarandache, Only Problems, Not Solutions!, Xiquan Publ., Phoenix-Chicago, 1993.
• Index entries for 10-automatic sequences.

Crossrefs

Cf. A014263, A103181, A196564.

Programs

Haskell

import Data.List (findIndices)
a007957 n = a007957_list !! (n-1)
a007957_list = findIndices (> 0) a196564_list
a196564 n = length [d | d <- show n, d `elem` "13579"]
a196564_list = map a196564 [0..]
-- Reinhard Zumkeller, Oct 04 2011

Mathematica

Select[Range[100],Count[IntegerDigits[#],?OddQ]>0&] (* _Harvey P. Dale, Sep 06 2017 *)

PARI

is(n)=my(v=vecsort(eval(Vec(Str(n)))%2,,8));v[#v] \\ Charles R Greathouse IV, Jul 25 2012

Formula

a(n) = n + O(n^0.69897...) where the constant is A153268. - Charles R Greathouse IV, Jul 25 2012