A044431 - OEIS

A044431

Numbers n such that string 9,9 occurs in the base 10 representation of n but not of n-1.

99, 199, 299, 399, 499, 599, 699, 799, 899, 990, 1099, 1199, 1299, 1399, 1499, 1599, 1699, 1799, 1899, 1990, 2099, 2199, 2299, 2399, 2499, 2599, 2699, 2799, 2899, 2990, 3099, 3199, 3299, 3399, 3499, 3599, 3699, 3799, 3899

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..39.

MATHEMATICA

SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {9, 9}]>0, 1, 0], {n, 4000}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 27 2019 *)

CROSSREFS

Sequence in context: A033674 A043526 A031500 * A044812 A221373 A260242

Adjacent sequences: A044428 A044429 A044430 * A044432 A044433 A044434

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved