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Primes of the form 2^k + 31.
1

%I #23 Nov 08 2023 14:49:11

%S 47,4127,68719476767,

%T 3599131035634557106248430806148785487095757694641533306480604458089470064537190296255232548883112685719936728506816716098566612844395439751206812144692131084107807

%N Primes of the form 2^k + 31.

%C Associated values of k are 4, 12, 36, 540, 844, 1192, ... . - _M. F. Hasler_, Nov 13 2010

%F a(n) = 2^A247952(n) + 31. - _Elmo R. Oliveira_, Nov 08 2023

%t a = Delete[Union[Flatten[Table[If [PrimeQ[2^n + 31] == True, 2^n + 31, 0], {n, 1, 400}]]], 1]

%o (Magma) [a: n in [0..750] | IsPrime(a) where a is 2^n+31] // _Vincenzo Librandi_, Nov 13 2010

%o (PARI) for(n=0,999, ispseudoprime(p=2^n+31) & print1(p", ")) \\ _M. F. Hasler_, Nov 13 2010

%Y Cf. A000040, A247952 (associated values of k).

%K nonn

%O 1,1

%A _Roger L. Bagula_, Mar 02 2005