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Search: id:A066926
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| A066926 |
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Numbers n having a partition n=sum x_i for which sum n/x_i is also a partition of n. |
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+0
5
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| 1, 4, 9, 16, 18, 24, 25, 30, 36, 40, 48, 49, 60, 64, 70, 72, 81, 84, 90, 96, 100, 105, 108, 112, 120, 121, 126, 132, 144, 150, 154, 156, 160, 162, 168, 169, 180, 192, 196, 198, 204, 208, 210, 216, 220, 225, 228, 234, 240, 250, 252, 256, 264, 270, 273, 276, 280
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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60 is in the sequence because 60 has a partition 4+5+5+10+12+12+12 for which 60/4+60/5+60/5+60/10+60/12+60/12+60/12=5+5+5+6+12+12+15 is also a partition of 60.
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MATHEMATICA
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Partitionable[n_, x_, y_, terms_] := If[Length[terms]==0||x<0||y<0, False, If[x==0&&y==0, True, If[IntegerQ[n/First[terms]]&&Partitionable[n, x-First[terms], y-n/First[terms], terms], True, Partitionable[n, x, y, Rest[terms]]]]]; TestNum[n_] := Partitionable[n, n, n, Divisors[n]]; Select[Range[100], TestNum]
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CROSSREFS
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Cf. A066925.
Sequence in context: A010393 A010425 A072903 this_sequence A066925 A122379 A104020
Adjacent sequences: A066923 A066924 A066925 this_sequence A066927 A066928 A066929
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KEYWORD
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nonn,nice
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AUTHOR
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David Eppstein (eppstein(AT)ics.uci.edu), Jan 23 2002
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EXTENSIONS
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More terms from Dean Hickerson (dean.hickerson(AT)yahoo.com), Jan 27 2002
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