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%I #17 Mar 28 2023 03:48:36
%S 0,1,3,7,9,19,27,33,147,639,12243,41427,44287,44449
%N Numbers k such that 2^k + k + 2 is prime.
%C If it exists, a(12) > 30000.
%C a(15) > 100000. - _Michael S. Branicky_, Mar 27 2023
%t Select[Range[0, 2047], PrimeQ[2^# + # + 2] &] (* _Alonso del Arte_, Jul 23 2019 *)
%o (PARI) for(n=0,15000,my(x=2^n+n+2); if(ispseudoprime(x), print1(n,", ")))
%Y A052968, A187733.
%K nonn,more,hard
%O 1,3
%A _Hugo Pfoertner_, Jul 23 2019
%E a(12)-a(14) from _Michael S. Branicky_, Mar 26 2023
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