A043979 Numbers k such that 2 and 7 occur juxtaposed in the base-9 representation of k but not of k+1.

25, 65, 106, 146, 187, 233, 268, 308, 349, 389, 430, 470, 511, 551, 593, 632, 673, 713, 754, 794, 835, 875, 916, 962, 997, 1037, 1078, 1118, 1159, 1199, 1240, 1280, 1322, 1361, 1402, 1442, 1483, 1523, 1564, 1604, 1645, 1691

Offset

1,1

Links

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

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n, 9], {2, 7}]>0 || SequenceCount[ IntegerDigits[n, 9], {7, 2}]>0 , 1, 0], {n, 1700}], {1, 0}][[All, 1]] (* Harvey P. Dale, Aug 29 2022 *)

Crossrefs

Cf. A007095.

Sequence in context: A121387 A039376 A043199 * A033682 A020283 A350207

Adjacent sequences: A043976 A043977 A043978 * A043980 A043981 A043982

Keyword

nonn,base

Author

Clark Kimberling

Status

approved