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A164884 a(n) = image of n under the base-2 Kaprekar map n -> (n with digits sorted into descending order) - (n with digits sorted into ascending order). 22
0, 0, 1, 0, 3, 3, 3, 0, 7, 9, 9, 7, 9, 7, 7, 0, 15, 21, 21, 21, 21, 21, 21, 15, 21, 21, 21, 15, 21, 15, 15, 0, 31, 45, 45, 49, 45, 49, 49, 45, 45, 49, 49, 45, 49, 45, 45, 31, 45, 49, 49, 45, 49, 45, 45, 31, 49, 45, 45, 31, 45, 31, 31, 0, 63, 93, 93, 105, 93, 105, 105, 105, 93, 105, 105 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,5
LINKS
Indranil Ghosh, Table of n, a(n) for n = 0..16384 (terms 0..1024 from Joseph Myers)
EXAMPLE
For n = 17, 17_10 = 10001_2. So, a(17) = 11000_2 - 11_2 = 24 - 3 = 21. - Indranil Ghosh, Feb 01 2017
MATHEMATICA
a[n_] := With[{dd = IntegerDigits[n, 2]}, FromDigits[ReverseSort[dd], 2] - FromDigits[Sort[dd], 2]];
a /@ Range[0, 100] (* Jean-François Alcover, Jan 08 2020 *)
PROG
(Python)
def A164884(n):
return int("".join(sorted(bin(n)[2:], reverse=True)), 2)-int("".join(sorted(bin(n)[2:])), 2) # Indranil Ghosh, Feb 01 2017
CROSSREFS
In other bases: A164993 (base 3), A165012 (base 4), A165032 (base 5), A165051 (base 6), A165071 (base 7), A165090 (base 8), A165110 (base 9), A151949 (base 10).
Sequence in context: A126660 A202698 A320785 * A357073 A019801 A086634
KEYWORD
base,nonn
AUTHOR
Joseph Myers, Aug 29 2009
EXTENSIONS
Cross-references edited by Joseph Myers, Sep 04 2009
STATUS
approved

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Last modified March 28 07:48 EDT 2024. Contains 371235 sequences. (Running on oeis4.)