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A043245
Numbers k such that 3 and 9 occur juxtaposed in the base-10 representation of k but not of k-1.
0
39, 93, 139, 193, 239, 293, 339, 390, 439, 493, 539, 593, 639, 693, 739, 793, 839, 893, 930, 993, 1039, 1093, 1139, 1193, 1239, 1293, 1339, 1390, 1439, 1493, 1539, 1593, 1639, 1693, 1739, 1793, 1839, 1893, 1930, 1993, 2039
OFFSET
1,1
MATHEMATICA
SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {3, 9}]>0 || SequenceCount[ IntegerDigits[n], {9, 3}]>0, 1, 0], {n, 2100}], {0, 1}][[All, 2]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 22 2020 *)
CROSSREFS
Sequence in context: A020168 A063318 A039422 * A044025 A062668 A158339
KEYWORD
nonn,base
STATUS
approved