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A109730
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Lesser of twin admirable numbers: k such that k and k+2 are both admirable numbers.
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3
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40, 54, 102, 138, 222, 364, 366, 474, 532, 642, 834, 1036, 1146, 1372, 1504, 1876, 1986, 2994, 3052, 3556, 4396, 4564, 5514, 5572, 5622, 6198, 6412, 6522, 7026, 7912, 7924, 8202, 8596, 8706, 9424, 9714, 10444, 10722, 11226, 11406, 12066, 12964
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OFFSET
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1,1
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COMMENTS
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Conjecture: Sequence is infinite.
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LINKS
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MATHEMATICA
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Select[Range[13000], MemberQ[Most[Divisors[#]], (DivisorSigma[1, #]-2*#)/2] && MemberQ[Most[Divisors[#+2]], (DivisorSigma[1, #+2]-2*(#+2))/2]&] (* James C. McMahon, Mar 29 2024 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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