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Search: id:A074849
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| A074849 |
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4-infinitary perfect numbers: n such that 4-infinitary-sigma(n)=2*n. |
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+0
2
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| 6, 28, 36720, 222768, 12646368, 5154170112, 34725010231296
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OFFSET
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0,1
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COMMENT
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Here 4-infinitary-sigma(a) means sum of 4-infinitary-divisor of a. If n=Product p(i)^r(i) and d=Product p(i)^s(i), each s(i) has a digit a<=b in its 4-ary expansion everywhere that the corresponding r(i) has a digit b, then d is a 4-infinitary-divisor of n.
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EXAMPLE
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Factorizations: 2*3, 2^2*7, 2^4*3^3*5*17, 2^4*3^2*7*13*17, 2^5*3^4*7*17*41, 2^8*3^2*7*13^2*31*61, 2^12*3^5*7*11*41*43*257.
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CROSSREFS
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Sequence in context: A095723 A057246 A154895 this_sequence A100874 A156927 A164274
Adjacent sequences: A074846 A074847 A074848 this_sequence A074850 A074851 A074852
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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), Sep 10 2002
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