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A043230 Numbers k such that 1 and 7 occur juxtaposed in the base-10 representation of k but not of k-1. 0
17, 71, 117, 170, 217, 271, 317, 371, 417, 471, 517, 571, 617, 671, 710, 771, 817, 871, 917, 971, 1017, 1071, 1117, 1170, 1217, 1271, 1317, 1371, 1417, 1471, 1517, 1571, 1617, 1671, 1700, 1817, 1871, 1917, 1971, 2017, 2071 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..41.

MATHEMATICA

SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {1, 7}]>0 || SequenceCount[IntegerDigits[n], {7, 1}]>0, 1, 0], {n, 2100}], {0, 1}][[All, 2]] (* Harvey P. Dale, Oct 17 2021 *)

CROSSREFS

Sequence in context: A179039 A152295 A039407 * A044010 A106921 A105414

Adjacent sequences: A043227 A043228 A043229 * A043231 A043232 A043233

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified February 3 18:13 EST 2023. Contains 360044 sequences. (Running on oeis4.)