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A135977
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Mersenne composites (A065341) with exactly 3 prime factors.
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8
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OFFSET
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1,1
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LINKS
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FORMULA
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MATHEMATICA
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k = {}; Do[If[ ! PrimeQ[2^Prime[n] - 1], c = FactorInteger[2^Prime[n] - 1]; d = Length[c]; If[d == 3, AppendTo[k, 2^Prime[n] - 1]]], {n, 1, 40}]; k
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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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