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Search: id:A072228
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| A072228 |
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Numbers n such that n = the sum of the reverses of the proper divisors of n. |
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+0
2
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OFFSET
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1,1
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COMMENT
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I call these numbers "anti-perfect" (compare with the picture-perfect numbers A069942). These are all the anti-perfect numbers up to 3 * 10^6.
Next term is greater than 300000000. - Farideh Firoozbakht (mymontain(AT)yahoo.com), Dec 23 2004
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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}]
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CROSSREFS
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Cf. A069942, A101701.
Adjacent sequences: A072225 A072226 A072227 this_sequence A072229 A072230 A072231
Sequence in context: A064382 A080358 A156936 this_sequence A056238 A041853 A113900
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KEYWORD
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base,more,nonn,nice
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Jul 05 2002
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EXTENSIONS
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One more term from Farideh Firoozbakht (mymontain(AT)yahoo.com), Dec 23 2004
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