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A231573
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Composite numbers n such that lambda(n) divides 6n-6, where lambda is the Carmichael lambda function (A002322).
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4
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4, 6, 8, 9, 12, 14, 15, 18, 21, 24, 28, 35, 36, 39, 42, 45, 56, 63, 65, 66, 72, 76, 84, 91, 105, 117, 126, 133, 153, 168, 186, 195, 231, 247, 252, 259, 273, 276, 315, 341, 344, 396, 435, 455, 481, 504, 532, 561, 585, 616, 645, 651, 671, 703, 804, 819, 861
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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 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[6 (# -1)/ CarmichaelLambda[#]] &]
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PROG
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(PARI) is(n)=!isprime(n) && (6*n-6)%lcm(znstar(n)[2])==0 && n>1 \\ _Charles R Greathouse IV_, Nov 13 2013
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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_José María Grau Ribas_, Nov 11 2013
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STATUS
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approved
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