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A043208 Numbers k such that 4 and 7 occur juxtaposed in the base-9 representation of k but not of k-1. 0
43, 67, 124, 148, 205, 229, 286, 310, 367, 387, 448, 472, 529, 553, 603, 634, 691, 715, 772, 796, 853, 877, 934, 958, 1015, 1039, 1096, 1116, 1177, 1201, 1258, 1282, 1332, 1363, 1420, 1444, 1501, 1525, 1582, 1606, 1663, 1687 (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], {4, 7}]>0 || SequenceCount[IntegerDigits[n, 9], {7, 4}]>0, 1, 0], {n, 2000}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jul 28 2018 *)

CROSSREFS

Cf. A007095.

Sequence in context: A139917 A146334 A039385 * A043988 A139499 A201688

Adjacent sequences:  A043205 A043206 A043207 * A043209 A043210 A043211

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified November 27 16:35 EST 2021. Contains 349394 sequences. (Running on oeis4.)