A044015 Numbers k such that 2 and 5 occur juxtaposed in the base-10 representation of k but not of k+1.

25, 52, 125, 152, 225, 259, 325, 352, 425, 452, 529, 552, 625, 652, 725, 752, 825, 852, 925, 952, 1025, 1052, 1125, 1152, 1225, 1259, 1325, 1352, 1425, 1452, 1529, 1552, 1625, 1652, 1725, 1752, 1825, 1852, 1925, 1952, 2025

Offset

1,1

Links

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

Mathematica

SequencePosition[Table[If[SequenceCount[IntegerDigits[n], {2, 5}]>0 || SequenceCount[ IntegerDigits[n], {5, 2}]>0, 1, 0], {n, 2100}], {1, 0}][[All, 1]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, May 14 2017 *)

Crossrefs

Sequence in context: A199990 A201057 A043235 * A118304 A117472 A146633

Adjacent sequences: A044012 A044013 A044014 * A044016 A044017 A044018

Keyword

nonn,base

Author

Clark Kimberling

Status

approved