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A043248 Numbers n such that 4 and 7 occur juxtaposed in the base 10 representation of n but not of n-1. 0
47, 74, 147, 174, 247, 274, 347, 374, 447, 470, 547, 574, 647, 674, 740, 774, 847, 874, 947, 974, 1047, 1074, 1147, 1174, 1247, 1274, 1347, 1374, 1447, 1470, 1547, 1574, 1647, 1674, 1740, 1774, 1847, 1874, 1947, 1974, 2047 (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], {4, 7}]>0 || SequenceCount[ IntegerDigits[n], {7, 4}]>0, 1, 0], {n, 2100}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jun 20 2019 *)

CROSSREFS

Sequence in context: A092178 A165335 A039425 * A044028 A126095 A132259

Adjacent sequences:  A043245 A043246 A043247 * A043249 A043250 A043251

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified June 2 07:15 EDT 2020. Contains 334767 sequences. (Running on oeis4.)