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%I #18 Sep 19 2018 03:02:51
%S 6,10,14,15,21,22,26,33,34,38,39,46,51,57,58,62,65,69,74,82,85,86,87,
%T 93,94,106,111,118,122,123,129,133,134,141,142,145,146,158,159,166,
%U 177,178,183,185,194,201,202,205,206,213,214,217,218,219,226,237
%N Squarefree semiprimes s=p*q, p<q, such that 2^s mod s = 2^p.
%C 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
%H Harvey P. Dale, <a href="/A180074/b180074.txt">Table of n, a(n) for n = 1..1000</a>
%t 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 *)
%o (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
%Y Cf. A006881, A015910, A162730, A179976.
%K nonn
%O 1,1
%A _Juri-Stepan Gerasimov_, Jan 14 2011
%E Definition and terms corrected by _R. J. Mathar_, Jan 14 2011
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