login

Reminder: The OEIS is hiring a new managing editor, and the application deadline is January 26.

Sum of two consecutive primes of the form 2^x+1 (including Fermat primes and 2).
0

%I #11 Jun 21 2021 18:33:58

%S 5,8,22,274,65794

%N Sum of two consecutive primes of the form 2^x+1 (including Fermat primes and 2).

%e a(1) = [2^0+1] + [2^(2^0)+1]

%e a(2) = [2^(2^0)+1] + [2^(2^1)+1]

%e a(3) = [2^(2^1)+1] + [2^(2^2)+1]

%e a(4) = [2^(2^2)+1] + [2^(2^3)+1]

%e a(5) = [2^(2^3)+1] + [2^(2^4)+1]

%t Total/@Partition[Select[2^Range[0,50]+1,PrimeQ],2,1] (* _Harvey P. Dale_, Jun 21 2021 *)

%Y Cf. A092506, A019434, A063897.

%K nonn,more

%O 1,1

%A _Jorge Coveiro_, Apr 12 2004

%E Offset corrected by _Arkadiusz Wesolowski_, Oct 22 2011