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Search: id:A052396
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| A052396 |
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(+2)-sigma perfect numbers: numbers such that (+2)sigma(n)=2*n, where if n=Product p(i)^r(i) then (+2)sigma(n)=Product (2+Sum p(i)^s(i), s(i)=1 to r(i)), e.g. (+2)sigma(6)=(2+2)*(2+3)=20. |
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+0
3
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| 2, 4, 8, 16, 32, 63, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 34587, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 170271081
(list; graph; listen)
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OFFSET
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1,1
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EXAMPLE
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Factorizations: even examples 2,2^2,2^3,2^4,...; odd examples 3^2*7 a(6), 3^4*7*61 a(17), 3^6*7*61*547 a(30).
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CROSSREFS
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Sequence in context: A135493 A111663 A054043 this_sequence A051040 A006261 A062259
Adjacent sequences: A052393 A052394 A052395 this_sequence A052397 A052398 A052399
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KEYWORD
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nonn
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AUTHOR
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Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp) Mar 13 2000
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EXTENSIONS
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Corrected by Franklin T. Adams-Watters, Oct 25 2006
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