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A268139
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Semiprimes of the form 3*n*2^n - 3*n - 2^(2+n) + 4.
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0
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OFFSET
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1,1
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LINKS
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MATHEMATICA
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Select[Table[3 n 2^n - 3 n - 2^(2 + n) + 4, {n, 250}], PrimeOmega[#] == 2 &]
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PROG
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(Magma) IsSemiprime:= func<n | &+[d[2]: d in Factorization(n)] eq 2>; [s: n in [2..240] | IsSemiprime(s) where s is 3*n*2^n-3*n-2^(2+n)+4];
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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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