A043142 - OEIS

A043142

Numbers k such that 2 and 3 occur juxtaposed in the base-7 representation of k but not of k-1.

17, 23, 66, 72, 115, 119, 161, 170, 213, 219, 262, 268, 311, 317, 360, 366, 409, 415, 458, 462, 504, 513, 556, 562, 605, 611, 654, 660, 703, 709, 752, 758, 801, 805, 833, 899, 905, 948, 954, 997, 1003, 1046, 1052, 1095, 1101

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OFFSET

1,1

LINKS

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

MATHEMATICA

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 7], {2, 3}]>0 || SequenceCount[IntegerDigits[n, 7], {3, 2}]>0, 1, 0], {n, 1200}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 26 2017 *)

CROSSREFS

Cf. A007093.

Sequence in context: A152292 A214493 A039319 * A043922 A260179 A100473

Adjacent sequences: A043139 A043140 A043141 * A043143 A043144 A043145

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved