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%I #18 May 07 2025 14:58:02
%S 8,32,512,8192,2097152,33554432,8589934592,137438953472,
%T 35184372088832,144115188075855872,2305843009213693952,
%U 9444732965739290427392,2417851639229258349412352,38685626227668133590597632,9903520314283042199192993792
%N a(n) = 2^(2*prime(n) - 1).
%t 2^(2Prime[Range[20]]-1) (* _Harvey P. Dale_, Dec 01 2017 *)
%o (Magma) [2^(2*p-1): p in PrimesUpTo(200)]; // _Vincenzo Librandi_, Dec 15 2010
%o (PARI) a(n)=2^(2*prime(n)-1) \\ _Charles R Greathouse IV_, Jul 02 2013
%Y Cf. A000040, A000079, A076274, A139287, A139288, A139289, A139290, A139291, A139292, A139293, A139294, A139306.
%K nonn,less
%O 1,1
%A _Omar E. Pol_, Apr 13 2008
%E Corrected and extended by _Harvey P. Dale_, Dec 01 2017