A043099 Numbers k such that 1 and 2 occur juxtaposed in the base-3 representation of k but not of k-1.

5, 7, 14, 21, 25, 32, 34, 41, 59, 61, 63, 75, 79, 86, 88, 95, 102, 106, 113, 115, 122, 167, 169, 176, 183, 187, 189, 221, 223, 225, 237, 241, 248, 250, 257, 264, 268, 275, 277, 284, 302, 304, 306, 318, 322, 329, 331, 338, 345, 349

Offset

1,1

Links

Table of n, a(n) for n=1..50.

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 3], {1, 2}]>0 || SequenceCount[ IntegerDigits[n, 3], {2, 1}]>0, 1, 0], {n, 400}], {0, 1}][[All, 2]] (* Harvey P. Dale, Nov 08 2022 *)

Crossrefs

Cf. A007089.

Sequence in context: A314351 A314352 A314353 * A030755 A170827 A314354

Adjacent sequences: A043096 A043097 A043098 * A043100 A043101 A043102

Keyword

nonn,base

Author

Clark Kimberling

Status

approved