A164993 a(n) = image of n under the base-3 Kaprekar map n -> (n with digits sorted into descending order) - (n with digits sorted into ascending order)

0, 0, 0, 2, 0, 2, 4, 2, 0, 8, 8, 16, 8, 0, 8, 16, 8, 8, 16, 16, 16, 16, 8, 8, 16, 8, 0, 26, 32, 58, 32, 26, 52, 58, 52, 58, 32, 26, 52, 26, 0, 26, 52, 26, 32, 58, 52, 58, 52, 26, 32, 58, 32, 26, 52, 58, 64, 58, 52, 58, 64, 58, 52, 58, 52, 58, 52, 26, 32, 58, 32, 26, 64, 58, 52, 58, 32

Offset

0,4

Links

Indranil Ghosh, Table of n, a(n) for n = 0..19683 (terms 0..2187 from Joseph Myers)

Index entries for the Kaprekar map

Example

For n = 10, 10_10 = 101_3. So, a(10) = 110_3 - 11_3 = 12 - 4 = 8. - Indranil Ghosh, Feb 02 2017

Mathematica

a[n_] := With[{dd = IntegerDigits[n, 3]}, FromDigits[ReverseSort[dd], 3] - FromDigits[Sort[dd], 3]];
a /@ Range[0, 100] (* Jean-François Alcover, Jan 08 2020 *)

Crossrefs

Cf. A164994.

In other bases: A164884 (base 2), A165012 (base 4), A165032 (base 5), A165051 (base 6), A165071 (base 7), A165090 (base 8), A165110 (base 9), A151949 (base 10).

Sequence in context: A055947 A015910 A182256 * A305572 A223487 A226911

Adjacent sequences: A164990 A164991 A164992 * A164994 A164995 A164996

Keyword

base,nonn

Author

Joseph Myers, Sep 04 2009

Status

approved