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%I #4 Nov 13 2020 18:45:17
%S 7,13,19,61,67,1021,4093,4099,16381,65539,262147,1048573,4194301,
%T 16777213,268435459,1073741827,19342813113834066795298819,
%U 19807040628566084398385987581,83076749736557242056487941267521533
%N Prime numbers of the form 4^k +- 3.
%C Subset of A122834.
%t Select[Flatten[Table[4^n+{3,-3},{n,100}]],PrimeQ]//Union (* _Harvey P. Dale_, Nov 13 2020 *)
%Y Cf. A000040, A000668, A122834, A144231
%K nonn
%O 1,1
%A _Reikku Kulon_, Sep 15 2008