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Search: id:A066925
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| A066925 |
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Numbers n having a partition n=sum x_i for which sum n/x_i is the same 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, 64, 70, 72, 81, 84, 90, 96, 100, 108, 112, 120, 121, 126, 144, 150, 154, 160, 162, 168, 169, 180, 192, 196, 198, 204, 208, 210, 216, 220, 225, 228, 234, 240, 250, 252, 256, 264, 270, 276, 280, 286, 288, 289, 294
(list; graph; listen)
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OFFSET
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1,2
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EXAMPLE
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24 is in the sequence because 24=2+4+6+12 and 12/2+12/4+12/6+12/12 gives the same partition 2+4+6+12.
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MATHEMATICA
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SelfInvPart[n_, x_, terms_] := If[Length[terms]==0||x<0, False, If[x==0, True, If[IntegerQ[Sqrt[n]]&&SelfInvPart[n, x-Sqrt[n], terms], True, If[IntegerQ[n/First[terms]]&&SelfInvPart[n, x-First[terms]-n/First[terms], terms], True, SelfInvPart[n, x, Rest[terms]]]]]]; TestSelfInv[n_] := SelfInvPart[n, n, Divisors[n]]; Select[Range[100], TestSelfInv]
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CROSSREFS
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Cf. A066926.
Sequence in context: A010425 A072903 A066926 this_sequence A122379 A104020 A066694
Adjacent sequences: A066922 A066923 A066924 this_sequence A066926 A066927 A066928
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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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