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Search: id:A045796
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| A045796 |
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Indices of USS perfect numbers. |
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+0
2
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| 2, 2, 3, 3, 2, 5, 2, 3, 4, 2, 2, 4, 4, 2, 2, 4, 7, 4, 6, 3, 4, 5, 3, 4, 5, 4, 5, 3, 4, 4, 2, 5, 4, 6, 4, 8, 7, 6, 4, 5, 3, 2, 4, 5, 7, 7, 4, 4, 2, 9, 5
(list; graph; listen)
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OFFSET
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0,1
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FORMULA
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a(n)=usigma(sigma(A045795(n)))/A045795(n).
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MAPLE
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A034448 := proc(n) local ans, i: ans := 1: for i from 1 to nops(ifactors(n)[ 2 ]) do ans := ans*(1+ifactors(n)[2][i][1]^ifactors(n)[2][i][2]): od: RETURN(ans) end: isA045795 := proc(n) if A034448(numtheory[sigma](n)) mod n = 0 then A034448(numtheory[sigma](n))/n ; else -1 ; fi ; end: A045796 := proc() local n, a : n := 2: while true do a := isA045795(n) ; if a>=0 then printf("%d, ", a) ; fi ; n := n+1: od : end: A045796() ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 26 2007
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CROSSREFS
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Cf. A045795, A034448.
Sequence in context: A039643 A154258 A167618 this_sequence A127684 A036012 A084401
Adjacent sequences: A045793 A045794 A045795 this_sequence A045797 A045798 A045799
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KEYWORD
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nonn,more
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AUTHOR
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Yasutoshi Kohmoto (zbi74583(AT)boat.zero.ad.jp)
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EXTENSIONS
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Corrected and extended by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jun 26 2007
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