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A072815
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Sum of proper divisors of 6n + 1.
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0
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0, 1, 1, 1, 6, 1, 1, 1, 8, 17, 1, 1, 1, 1, 23, 21, 1, 1, 1, 29, 12, 1, 27, 1, 35, 1, 1, 1, 14, 48, 1, 29, 1, 1, 47, 1, 39, 1, 1, 53, 1, 33, 35, 45, 59, 1, 1, 1, 18, 65, 51, 1, 1, 41, 84, 1, 1, 57, 1, 77, 20, 1, 1, 1, 101, 41, 1, 45, 89, 1, 68
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,5
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COMMENTS
| the square root of t(n) < s(t(4n-1, 4n-2, 4n-3, 4n-4)) < s(t(4n)).
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LINKS
| Eric Weisstein's World of Mathematics, Perfect Numbers
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FORMULA
| s(t(n)), where t(n)=6n + 1 and s(n) is the restricted divisor function.
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EXAMPLE
| a(1) = s(t(1))=1 since t(1)=7 and s(7)=1 under the definition of the restricted divisor function.
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CROSSREFS
| Sequence in context: A064793 A034460 A063919 * A080304 A166142 A183092
Adjacent sequences: A072812 A072813 A072814 * A072816 A072817 A072818
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KEYWORD
| nonn
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AUTHOR
| Hisanobu Shinya (ilikemathematics(AT)hotmail.com), Jul 14 2002
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