A043987 Numbers k such that 4 and 6 occur juxtaposed in the base-9 representation of k but not of k+1.

42, 58, 123, 139, 204, 220, 285, 301, 366, 386, 447, 463, 530, 544, 609, 625, 690, 706, 771, 787, 852, 868, 933, 949, 1014, 1030, 1095, 1115, 1176, 1192, 1259, 1273, 1338, 1354, 1419, 1435, 1500, 1516, 1581, 1597, 1662, 1678

Offset

1,1

Links

Table of n, a(n) for n=1..42.

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 9], {4, 6}]>0 || SequenceCount[ IntegerDigits[ n, 9], {6, 4}]>0, 1, 0], {n, 1700}], {1, 0}] [[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Jan 25 2017 *)

Crossrefs

Cf. A007095.

Sequence in context: A080971 A039384 A043207 * A300378 A300680 A053323

Adjacent sequences: A043984 A043985 A043986 * A043988 A043989 A043990

Keyword

nonn,base

Author

Clark Kimberling

Status

approved