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%I #22 Mar 22 2023 12:30:19
%S 1,2,3,4,7,13,16,32,64,71,103,541,1091,1367,1627,4177,9011,9551,36913,
%T 43063,49681,57917,483611,877843,2215303,2704981,3598867
%N Numbers n such that 3^n has the form 2p-+1 where p is prime.
%C For the corresponding primes p see A088553.
%C For n > 1, numbers n such that (3^n + (-1)^n)/2 is prime. - _Thomas Ordowski_, Dec 26 2016
%t Select[Range[4200],Or@@PrimeQ[(3^#+{1,-1})/2]&] (* _Harvey P. Dale_, Mar 05 2013 *)
%Y Cf. A028491, A075081, A088553, A093625, A171381.
%K nonn,more
%O 1,2
%A _Lekraj Beedassy_, Jul 05 2004
%E More terms from _Ray Chandler_, Jul 09 2004
%E a(25)-a(27) (from A028491 and A171381) from _Tyler Busby_, Mar 22 2023
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