A043151 Numbers k such that 5 and 6 occur juxtaposed in the base-7 representation of k but not of k-1.

41, 47, 90, 96, 139, 145, 188, 194, 237, 243, 286, 329, 341, 384, 390, 433, 439, 482, 488, 531, 537, 580, 586, 629, 672, 684, 727, 733, 776, 782, 825, 831, 874, 880, 923, 929, 972, 1015, 1027, 1070, 1076, 1119, 1125, 1168, 1174

Offset

1,1

Links

Table of n, a(n) for n=1..45.

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 7], {5, 6}]>0 || SequenceCount[IntegerDigits[n, 7], {6, 5}]>0, 1, 0], {n, 1200}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Mar 23 2021 *)

Crossrefs

Cf. A007093.

Sequence in context: A243460 A186280 A039328 * A043931 A139219 A185658

Adjacent sequences: A043148 A043149 A043150 * A043152 A043153 A043154

Keyword

nonn,base

Author

Clark Kimberling

Status

approved