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A107846
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Number of duplicate digits of n.
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3
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,112
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COMMENTS
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LINKS
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FORMULA
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EXAMPLE
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a(11) = 1 because 11 has two total decimal digits but only one distinct digit (1) and 2-1=1.
Similarly, a(3653135) = 7 (total digits) - 4 (distinct digits: 1,3,5,6) = 3 (There are three duplicate digits here, namely, 3, 3 and 5).
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MATHEMATICA
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Table[Total[Select[DigitCount[n]-1, #>0&]], {n, 0, 120}] (* Harvey P. Dale, Jul 31 2013 *)
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PROG
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(Haskell)
import Data.List (sort, group)
a107846 = length . concatMap tail . group . sort . show :: Integer -> Int
(Python)
def a(n): return len(s:=str(n)) - len(set(s))
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CROSSREFS
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Cf. A055642 (Total decimal digits of n), A043537 (Distinct decimal digits of n).
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KEYWORD
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base,easy,nonn
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AUTHOR
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STATUS
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approved
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