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A071090
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Sum of middle divisors of n.
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8
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1, 1, 0, 2, 0, 5, 0, 2, 3, 0, 0, 7, 0, 0, 8, 4, 0, 3, 0, 9, 0, 0, 0, 10, 5, 0, 0, 11, 0, 11, 0, 4, 0, 0, 12, 6, 0, 0, 0, 13, 0, 13, 0, 0, 14, 0, 0, 14, 7, 5, 0, 0, 0, 15, 0, 15, 0, 0, 0, 16, 0, 0, 16, 8, 0, 17, 0, 0, 0, 17, 0, 23, 0, 0, 0, 0, 18, 0, 0, 18, 9, 0, 0, 19, 0, 0, 0, 19, 0, 19, 20, 0, 0
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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COMMENTS
| Divisors are in the half-open interval [sqrt(n/2), sqrt(n*2)).
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MATHEMATICA
| Table[Plus @@ Select[ Divisors[n], Sqrt[n/2] <= # < Sqrt[n*2] &], {n, 1, 95}]
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CROSSREFS
| Cf. A067742.
Sequence in context: A066442 A171388 A086134 * A105221 A061376 A058974
Adjacent sequences: A071087 A071088 A071089 * A071091 A071092 A071093
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com), May 27 2002
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EXTENSIONS
| Extended by Robert G. Wilson v (rgwv(AT)rgwv.com), May 30 2002
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