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A098949 Numbers where 9 is the only odd decimal digit. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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

MATHEMATICA

Select[Range[1000], DigitCount[ # ][[1]] == 0 && DigitCount[ # ][[3]] == 0 && DigitCount[ # ][[5]] == 0 && DigitCount[ # ][[7]] == 0 && DigitCount[ # ][[9]] >0 &] (* Stefan Steinerberger, Jun 06 2006 *)

Select[Range[1000], Union[Select[IntegerDigits[#], OddQ]]=={9}&] (* Harvey P. Dale, May 07 2019 *)

PROG

(Perl) for (0..1000) {

    print "$_, " if (/^[024689]*9[024689]*$/)

} # Charles R Greathouse IV, Oct 05 2011

CROSSREFS

Sequence in context: A002642 A032700 A322946 * A031296 A146869 A129397

Adjacent sequences:  A098946 A098947 A098948 * A098950 A098951 A098952

KEYWORD

base,easy,nonn

AUTHOR

Eric Angelini, Oct 21 2004

EXTENSIONS

More terms from Stefan Steinerberger, Jun 06 2006

First Mathematica program corrected by Harvey P. Dale, May 07 2019

STATUS

approved

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Last modified December 8 18:37 EST 2019. Contains 329865 sequences. (Running on oeis4.)