A043234 Numbers k such that 2 and 4 occur juxtaposed in the base-10 representation of k but not of k-1.

24, 42, 124, 142, 224, 240, 324, 342, 420, 442, 524, 542, 624, 642, 724, 742, 824, 842, 924, 942, 1024, 1042, 1124, 1142, 1224, 1240, 1324, 1342, 1420, 1442, 1524, 1542, 1624, 1642, 1724, 1742, 1824, 1842, 1924, 1942, 2024

Offset

1,1

Links

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

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {2, 4}]>0||SequenceCount[ IntegerDigits[ n], {4, 2}]>0, 1, 0], {n, 2500}], {0, 1}][[;; , 2]] (* Harvey P. Dale, Sep 15 2024 *)

Crossrefs

Sequence in context: A228844 A111948 A039411 * A044014 A087093 A118299

Adjacent sequences: A043231 A043232 A043233 * A043235 A043236 A043237

Keyword

nonn,base

Author

Clark Kimberling

Status

approved