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A231571
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Composite numbers n such that lambda(n) divides 4n-4, where lambda is the Carmichael lambda function (A002322).
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3
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4, 6, 8, 10, 12, 15, 16, 20, 24, 28, 30, 40, 48, 52, 60, 66, 70, 80, 85, 91, 112, 120, 130, 176, 190, 208, 232, 240, 276, 280, 286, 364, 370, 435, 451, 496, 520, 532, 561, 616, 703, 742, 910, 946, 976, 1036, 1105, 1128, 1288, 1387, 1456, 1729, 1770, 1891
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OFFSET
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1,1
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COMMENTS
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Conjecture: the relative asymptotic density of the Carmichael numbers in this sequence exists, is positive and smaller than 1.
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LINKS
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MATHEMATICA
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Select [1 + Range[100000], ! PrimeQ[#] && IntegerQ[4 (# -1)/ CarmichaelLambda[#]] &]
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PROG
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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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