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A072228
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Numbers k such that k equals the sum of the reverses of the proper divisors of k.
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3
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OFFSET
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1,1
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COMMENTS
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I call these numbers "anti-perfect" (compare with the picture-perfect numbers A069942).
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LINKS
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EXAMPLE
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The proper divisors of 285 are 1, 3, 5, 15, 19, 57, 95, with sum of reverses = 1 + 3 + 5 + 51 + 91 + 75 + 59 = 285. Therefore 285 is anti-perfect.
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MATHEMATICA
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f[n_] := FromDigits[Reverse[IntegerDigits[n]]]; Do[ If[n == Apply[Plus, Map[f, Drop[Divisors[n], -1]]], Print[n]], {n, 2, 10^7}]
Select[Range[15*10^7], Total[IntegerReverse[Most[Divisors[#]]]]==#&] (* Requires Mathematica version 10 or later *) (* The program takes a long time to run *) (* Harvey P. Dale, Aug 31 2016 *)
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CROSSREFS
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KEYWORD
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base,more,nonn,nice
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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