A043917 Numbers k such that 1 and 2 occur juxtaposed in the base-7 representation of k but not of k+1.

9, 15, 58, 69, 111, 113, 156, 162, 205, 211, 254, 260, 303, 309, 352, 358, 401, 412, 489, 499, 505, 548, 554, 597, 603, 646, 652, 695, 701, 783, 797, 799, 842, 848, 891, 897, 940, 946, 989, 995, 1038, 1044, 1087, 1098, 1140, 1142

Offset

1,1

Links

Table of n, a(n) for n=1..46.

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 7], {1, 2}]>0 || SequenceCount[ IntegerDigits[ n, 7], {2, 1}]>0, 1, 0], {n, 1200}], {1, 0}][[;; , 1]] (* Harvey P. Dale, Jun 03 2023 *)

Crossrefs

Cf. A007093.

Sequence in context: A276414 A175033 A043137 * A351499 A037378 A100663

Adjacent sequences: A043914 A043915 A043916 * A043918 A043919 A043920

Keyword

nonn,base

Author

Clark Kimberling

Status

approved