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A156903
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Numbers whose abundance is odd.
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3
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18, 36, 72, 100, 144, 162, 196, 200, 288, 324, 392, 400, 450, 576, 648, 784, 800, 882, 900, 968, 1152, 1296, 1352, 1458, 1568, 1600, 1764, 1800, 1936, 2178, 2304, 2450, 2500, 2592, 2704, 2916, 3042, 3136, 3200, 3528, 3600, 3872, 4050, 4356, 4608, 4624
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Seems to be a proper subset of A083211. [From Robert G. Wilson v (rgwv(AT)rgwv.com), Mar 30 2010]
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LINKS
| Eric Weisstein's World of Mathematics, Abundant Number
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EXAMPLE
| 18 is in the sequence because its divisors are {1,2,3,6,9,18} which sum to 39; so its abundance is 3.
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MATHEMATICA
| f[n_] := DivisorSigma[1, n] - 2 n; Select[ Range@ 10000, f@# > 0 && Mod[f@#, 2] == 1 &]
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CROSSREFS
| Cf. A005101. A proper subset of A083211.
Sequence in context: A087967 A070224 A083211 * A204824 A023149 A115550
Adjacent sequences: A156900 A156901 A156902 * A156904 A156905 A156906
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KEYWORD
| nonn
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AUTHOR
| Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 17 2009
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