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Search: id:A066240
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| A066240 |
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The floor(n/2)-perfect numbers, where f-perfect numbers for an arithmetical function f are defined in A066218. |
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+0
1
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OFFSET
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1,1
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LINKS
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J. Pe, On a Generalization of Perfect Numbers, J. Rec. Math., 31(3) (2002-2003), 168-172.
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EXAMPLE
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Let f(n) = floor(n/2). Then f(18) = 9 = 4+3+1+1+0 = f(9)+f(6)+f(3)+f(2)+f(1); so 18 is a term of the sequence.
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MATHEMATICA
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f[x_] := Floor[x/2]; Select[ Range[ 1, 10^5], 2 * f[ # ] == Apply[ Plus, Map[ f, Divisors[ # ] ] ] & ]
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CROSSREFS
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Sequence in context: A113541 A113542 A075865 this_sequence A115747 A001101 A088341
Adjacent sequences: A066237 A066238 A066239 this_sequence A066241 A066242 A066243
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KEYWORD
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nonn
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AUTHOR
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Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Dec 19 2001
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