A164885 - OEIS

A164885

Length of preperiodic part of trajectory of n under iteration of the base-2 Kaprekar map in A164884.

0, 1, 2, 1, 2, 2, 2, 1, 2, 0, 1, 2, 1, 2, 2, 1, 2, 1, 1, 1, 1, 0, 1, 2, 1, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 2, 1, 0, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 2, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1

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OFFSET

0,3

COMMENTS

All base-2 cycles are fixed points, so one less than A164886.

LINKS

Joseph Myers, Table of n, a(n) for n = 0..1024

Index entries for the Kaprekar map

MATHEMATICA

A164885[n_] := Length[FixedPointList[FromDigits[Reverse[#], 2] - FromDigits[#, 2] & [Sort[IntegerDigits[#, 2]]] &, n]] - 2;

Array[A164885, 100, 0] (* Paolo Xausa, Feb 05 2026 *)

CROSSREFS

Cf. A164884, A163205, A164886, A164887.

In other bases: A164995 (base 3), A165014 (base 4), A165034 (base 5), A165053 (base 6), A165073 (base 7), A165092 (base 8), A165112 (base 9), A151962 (base 10).

Sequence in context: A278495 A254623 A055188 * A084989 A128538 A381399

Adjacent sequences: A164882 A164883 A164884 * A164886 A164887 A164888

KEYWORD

base,nonn

AUTHOR

Joseph Myers, Aug 29 2009

EXTENSIONS

Cross-references edited by Joseph Myers, Sep 04 2009

STATUS

approved