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Search: id:A082731
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| A082731 |
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a(n) = smallest number k such that ms(k) - k = n, or 0 if no such number exists, where ms(k) = sum of divisors of k other than k. |
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+0
2
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| 6, 0, 20, 18, 12, 0, 8925, 196, 56, 0, 40, 0, 24, 0, 272, 0, 550, 100, 208, 36, 176, 0, 1312, 0, 112, 0, 80, 0, 48, 0, 945, 15376, 572, 0, 928, 0, 2205, 0, 5696, 162, 736, 1352, 9555, 0, 350, 0, 490, 0, 60, 0, 416, 72, 352, 0, 90, 0, 84, 0, 160, 968, 96, 0, 24704, 0, 108, 200
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Caution: so far a(n)=0 only indicates no k<2*10^6 exists; non-existance is not proved. - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 26 2007
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MAPLE
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A082731 := proc(n) local k; k := 1 ; while numtheory[sigma](k)-2*k <> n do k := k+1 ; if k = 2000000 then RETURN(0) ; fi ; od ; RETURN(k) ; end: seq(A082731(n), n=0..200) ; - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 26 2007
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CROSSREFS
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Cf. A082730.
Sequence in context: A069828 A057401 A019134 this_sequence A064381 A062254 A028849
Adjacent sequences: A082728 A082729 A082730 this_sequence A082732 A082733 A082734
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KEYWORD
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nonn
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AUTHOR
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Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Apr 14 2003
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jul 26 2007
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