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%I #12 Sep 18 2024 14:14:15
%S 3,9,13,15,25,49,55,69,115,2071,6249,13669,14215,14625,396127
%N Numbers k such that 2^(k+1) - k - 2 is prime.
%D Dean Hickerson, personal communication.
%F a(n) = A099439(n) - 1. - _Hugo Pfoertner_, Jul 24 2019
%o (PARI) for(n=1,5000, if(isprime(2^(n+1)-n-2),print(n)))
%Y Cf. A099439.
%K nonn,more
%O 1,1
%A _Jason Earls_, Aug 17 2001
%E More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 03 2008
%E a(15) from _Karsten Bonath_, Jun 07 2018