A043211 - OEIS

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A043211

Numbers k such that 5 and 7 occur juxtaposed in the base-9 representation of k but not of k-1.

52, 68, 133, 149, 214, 230, 295, 311, 376, 392, 457, 468, 538, 554, 612, 635, 700, 716, 781, 797, 862, 878, 943, 959, 1024, 1040, 1105, 1121, 1186, 1197, 1267, 1283, 1341, 1364, 1429, 1445, 1510, 1526, 1591, 1607, 1672, 1688

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

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

MATHEMATICA

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 9], {5, 7}]>0 || SequenceCount[IntegerDigits[n, 9], {7, 5}]>0, 1, 0], {n, 1700}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Nov 02 2017 *)

CROSSREFS

Cf. A007095.

Sequence in context: A124471 A107933 A039388 * A043991 A326235 A118148

Adjacent sequences: A043208 A043209 A043210 * A043212 A043213 A043214

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved