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A165012
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a(n) = image of n under the base-4 Kaprekar map n -> (n with digits sorted into descending order) - (n with digits sorted into ascending order).
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31
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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
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,5
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LINKS
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EXAMPLE
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For n = 11, 11_10 = 23_4. So, a(11) = 32_4 - 23_4 = 14 - 11 = 3. - Indranil Ghosh, Feb 02 2017
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MATHEMATICA
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b4km[n_]:=Module[{idn4=Sort[IntegerDigits[n, 4]]}, FromDigits[ Reverse[ idn4], 4]-FromDigits[idn4, 4]]; Array[b4km, 80, 0]
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PROG
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(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
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CROSSREFS
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KEYWORD
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base,nonn
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AUTHOR
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STATUS
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approved
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