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%I #11 Sep 05 2015 03:08:52
%S 9,13,21,25,27,35,41,53,63,81,123,333,381,413,1187,2265,3153,4211,
%T 4887,7359,14161,14643,17299,22107,31487,40235,46711
%N Numbers n such that n!! - 2^n is prime.
%C All terms are odd.
%C a(28) > 50000. - _Robert Price_, Sep 04 2015
%e 9 is in the sequence because 9!! - 2^9 = 433 is prime.
%t Select[Range[0, 50000], #!! - 2^# > 0 && PrimeQ[#!! - 2^#] &] (* _Robert Price_, Sep 04 2015 *)
%Y Cf. A124248.
%K more,nonn
%O 1,1
%A _Farideh Firoozbakht_, Nov 27 2006
%E Three more terms from _Ryan Propper_, Nov 05 2007
%E a(21)-a(27) from _Robert Price_, Sep 04 2015