A044006 Numbers k such that 1 and 3 occur juxtaposed in the base-10 representation of k but not of k+1.

13, 31, 113, 139, 213, 231, 319, 331, 413, 431, 513, 531, 613, 631, 713, 731, 813, 831, 913, 931, 1013, 1031, 1113, 1139, 1213, 1231, 1399, 1413, 1431, 1513, 1531, 1613, 1631, 1713, 1731, 1813, 1831, 1913, 1931, 2013, 2031

Offset

1,1

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {1, 3}]>0 || SequenceCount[ IntegerDigits[n], {3, 1}]>0, 1, 0], {n, 2100}], {1, 0}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Aug 18 2019 *)

Crossrefs

Sequence in context: A062339 A368051 A043226 * A179034 A179035 A007628

Adjacent sequences: A044003 A044004 A044005 * A044007 A044008 A044009

Keyword

nonn,base

Author

Clark Kimberling

Status

approved