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Primes of the form 2^k - k + 1.
6

%I #41 Mar 02 2022 12:03:21

%S 2,2,3,13,59,65521,262127,18014398509481931,288230376151711687,

%T 1267650600228229401496703205277,1329227995784915872903807060280344457

%N Primes of the form 2^k - k + 1.

%C The next term has 151 digits. - _Stefan Steinerberger_, Feb 11 2006

%H Vincenzo Librandi, <a href="/A100362/b100362.txt">Table of n, a(n) for n = 1..14</a>

%t Select[Table[2^n-n+1,{n,0,500}],PrimeQ] (* _Vincenzo Librandi_, Jul 18 2012 *)

%o (Magma) [ a: n in [0..200] | IsPrime(a) where a is 2^n-n+1 ]; // _Vincenzo Librandi_, Jul 18 2012

%o (Sage)

%o def list_a(k):

%o return [(2**i) - i + 1 for i in range(k) if (2**i) - i + 1 in Primes()] # _Giuseppe Bonaccorso_, Aug 15 2019

%Y Cf. A001580, A052007, A048744, A100357-A100361.

%K nonn,easy

%O 1,1

%A _Labos Elemer_, Nov 19 2004