A043197 Numbers k such that 2 and 5 occur juxtaposed in the base-9 representation of k but not of k-1.

23, 47, 104, 128, 185, 207, 266, 290, 347, 371, 423, 452, 509, 533, 590, 614, 671, 695, 752, 776, 833, 857, 914, 936, 995, 1019, 1076, 1100, 1152, 1181, 1238, 1262, 1319, 1343, 1400, 1424, 1481, 1505, 1562, 1586, 1643, 1665

Offset

1,1

Links

Table of n, a(n) for n=1..42.

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 9], {2, 5}]>0||SequenceCount[IntegerDigits[n, 9], {5, 2}]>0, 1, 0], {n, 2000}], {0, 1}][[;; , 2]] (* Harvey P. Dale, Jan 11 2025 *)

Crossrefs

Cf. A007095.

Sequence in context: A195058 A352291 A039374 * A043977 A373464 A042048

Adjacent sequences: A043194 A043195 A043196 * A043198 A043199 A043200

Keyword

nonn,base

Author

Clark Kimberling

Status

approved