

A165012


a(n) = image of n under the base4 Kaprekar map n > (n with digits sorted into descending order)  (n with digits sorted into ascending order).


31



0, 0, 0, 0, 3, 0, 3, 6, 6, 3, 0, 3, 9, 6, 3, 0, 15, 15, 30, 45, 15, 0, 15, 30, 30, 15, 15, 30, 45, 30, 30, 30, 30, 30, 30, 45, 30, 15, 15, 30, 30, 15, 0, 15, 45, 30, 15, 15, 45, 45, 45, 45, 45, 30, 30, 30, 45, 30, 15, 15, 45, 30, 15, 0, 63, 75, 138, 201, 75, 63, 126, 189, 138, 126
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OFFSET

0,5


LINKS

Indranil Ghosh, Table of n, a(n) for n = 0..16384 (terms 0..1024 from Joseph Myers)
Index entries for the Kaprekar map


EXAMPLE

For n = 11, 11_10 = 23_4. So, a(11) = 32_4  23_4 = 14  11 = 3.  Indranil Ghosh, Feb 02 2017


MATHEMATICA

b4km[n_]:=Module[{idn4=Sort[IntegerDigits[n, 4]]}, FromDigits[ Reverse[ idn4], 4]FromDigits[idn4, 4]]; Array[b4km, 80, 0]


PROG

(PARI) cons(m) = {local(b, r); r=0; b=1; for(i=1, matsize(m)[2], r=r+b*m[i]; b=b*4); r}
A165012(n) = {local(m, r); r=[]; m=n; while(m>0, r=concat(m%4, r); m=floor(m/4)); cons(vecsort(r, , 0))cons(vecsort(r, , 4))} \\ Michael B. Porter, Nov 05 2009


CROSSREFS

Cf. A165013.
In other bases: A164884 (base 2), A164993 (base 3), A165032 (base 5), A165051 (base 6), A165071 (base 7), A165090 (base 8), A165110 (base 9), A151949 (base 10).
Sequence in context: A226568 A038517 A055949 * A198126 A074694 A127803
Adjacent sequences: A165009 A165010 A165011 * A165013 A165014 A165015


KEYWORD

base,nonn


AUTHOR

Joseph Myers, Sep 04 2009


STATUS

approved



