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A180074
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Squarefree semiprimes s=p*q, p<q, such that 2^s mod s = 2^p.
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1
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6, 10, 14, 15, 21, 22, 26, 33, 34, 38, 39, 46, 51, 57, 58, 62, 65, 69, 74, 82, 85, 86, 87, 93, 94, 106, 111, 118, 122, 123, 129, 133, 134, 141, 142, 145, 146, 158, 159, 166, 177, 178, 183, 185, 194, 201, 202, 205, 206, 213, 214, 217, 218, 219, 226, 237
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OFFSET
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1,1
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COMMENTS
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It may seem that this is a subsequence of A162730, but it is not so, 131801 being the first counterexample. - Michel Marcus, Sep 19 2018
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LINKS
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MATHEMATICA
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f[n_]:=With[{f=FactorInteger[n][[All, 1]]}, PowerMod[ 2, Times@@f, Times@@f] == 2^f[[1]]]; Select[Range[250], PrimeOmega[#]==2&&SquareFreeQ[#]&&f[#]&] (* Harvey P. Dale, Jun 06 2017 *)
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PROG
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(PARI) isok(n) = {if ((bigomega(n) == 2) && (omega(n) == 2), my(p = factor(n)[1, 1]); lift(Mod(2, n)^n) == 2^p); } \\ Michel Marcus, Sep 19 2018
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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