

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
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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^(n1).  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



