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A365065
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Least k such that k*M(n)*M(n+4) + 1 is prime, where M(n) = A000668(n).
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2
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20, 18, 4, 22, 112, 28, 28, 52, 28, 616, 1288, 1342, 9988, 214, 7666, 3328, 21658, 18988, 6868, 22824, 10746, 3388, 59256
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OFFSET
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1,1
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COMMENTS
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If they exist, a(23) > 40809, a(24) > 2495, a(25) > 1473.
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LINKS
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MATHEMATICA
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Table[k=1; Monitor[Parallelize[While[True, If[PrimeQ[k*(2^MersennePrimeExponent[n]-1)*(2^(MersennePrimeExponent[n+4])-1)+1], Break[]]; k++]; k], k], {n, 1, 20}]
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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