A098949 Numbers where 9 is the only odd decimal digit.

9, 29, 49, 69, 89, 90, 92, 94, 96, 98, 99, 209, 229, 249, 269, 289, 290, 292, 294, 296, 298, 299, 409, 429, 449, 469, 489, 490, 492, 494, 496, 498, 499, 609, 629, 649, 669, 689, 690, 692, 694, 696, 698, 699, 809, 829, 849, 869, 889, 890, 892, 894, 896, 898

Offset: 1

Author

Eric Angelini, Oct 21 2004

Keywords

• base
• easy
• nonn

Comments

This is a regular language in base 10. - Charles R Greathouse IV, Oct 05 2011

The number of terms of this sequence that are smaller than 10^n is n*5^(n-1). - Stefan Steinerberger, Jun 06 2006

Any number of 9s is permitted. - Harvey P. Dale, May 07 2019

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..2000
• Index entries for 10-automatic sequences

Programs

Mathematica

Select[Range[1000], DigitCount[ # ][[1]] == 0 && DigitCount[ # ][[3]] == 0 && DigitCount[ # ][[5]] == 0 && DigitCount[ # ][[7]] == 0 && DigitCount[ # ][[9]] >0 &] (* Stefan Steinerberger, Jun 06 2006; corrected by Harvey P. Dale, May 07 2019 *)
Select[Range[1000],Union[Select[IntegerDigits[#],OddQ]]=={9}&] (* Harvey P. Dale, May 07 2019 *)

Perl

for (0..1000) {
    print "$_, " if (/^[024689]*9[024689]*$/)
} # Charles R Greathouse IV, Oct 05 2011

Python

def ok(n): return set(str(n)) & set("13579") == set("9")
print(list(filter(ok, range(899)))) # Michael S. Branicky, Sep 29 2021

Extensions

More terms from Stefan Steinerberger, Jun 06 2006