A043232 Numbers k such that 1 and 9 occur juxtaposed in the base-10 representation of k but not of k-1.

19, 91, 119, 190, 219, 291, 319, 391, 419, 491, 519, 591, 619, 691, 719, 791, 819, 891, 910, 991, 1019, 1091, 1119, 1190, 1219, 1291, 1319, 1391, 1419, 1491, 1519, 1591, 1619, 1691, 1719, 1791, 1819, 1891, 1900, 2019, 2091

Offset

1,1

Links

Table of n, a(n) for n=1..41.

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {1, 9}]>0||SequenceCount[ IntegerDigits[ n], {9, 1}]>0, 1, 0], {n, 2200}], {0, 1}][[;; , 2]] (* Harvey P. Dale, May 07 2023 *)

Crossrefs

Sequence in context: A157875 A039409 A038653 * A044012 A288485 A214532

Adjacent sequences: A043229 A043230 A043231 * A043233 A043234 A043235

Keyword

nonn,base

Author

Clark Kimberling

Status

approved