A043250 Numbers k such that 4 and 9 occur juxtaposed in the base-10 representation of k but not of k-1.

49, 94, 149, 194, 249, 294, 349, 394, 449, 490, 549, 594, 649, 694, 749, 794, 849, 894, 940, 994, 1049, 1094, 1149, 1194, 1249, 1294, 1349, 1394, 1449, 1490, 1549, 1594, 1649, 1694, 1749, 1794, 1849, 1894, 1940, 1994, 2049

Offset

1,1

Links

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

Mathematica

Transpose[SequencePosition[Table[If[MemberQ[Sort/@Partition[IntegerDigits[n], 2, 1], {4, 9}], 1, 0], {n, 2100}], {0, 1}]][[2]] (* The program uses the SequencePosition function from Mathematica version 10 *) (* Harvey P. Dale, Apr 28 2015 *)

Crossrefs

Sequence in context: A275419 A031180 A039427 * A044030 A165339 A131601

Adjacent sequences: A043247 A043248 A043249 * A043251 A043252 A043253

Keyword

nonn,base

Author

Clark Kimberling

Status

approved