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Numbers n such that n*2^n+(n+1) is prime.
1

%I #28 May 01 2016 07:45:22

%S 2,38,426,978,1530,5268,7238,8384,9696,11930,16164,40502

%N Numbers n such that n*2^n+(n+1) is prime.

%C a(6) (if it exists) > 4000. - _Hiroaki Yamanouchi_, Sep 22 2014

%C a(13) > 200000. - _Giovanni Resta_, May 01 2016

%t Select[Range[10^4], PrimeQ[#*2^# + (# + 1)] &] (* _Michael De Vlieger_, Mar 02 2015 *)

%o (PARI) for(n=1,10^6,if(ispseudoprime(n*2^n+(n+1)),print1(n,", "))); \\ _Joerg Arndt_, Mar 02 2015

%Y Cf. A046844 (corresponding primes).

%K hard,more,nonn

%O 1,1

%A _Felice Russo_

%E a(4)-a(5) from _Hiroaki Yamanouchi_, Sep 22 2014

%E New name from _Hiroaki Yamanouchi_, Sep 22 2014

%E Term a(6)-a(10) (pseudoprimes) from _Joerg Arndt_, Mar 02 2015

%E a(11)-a(12) (pseudoprimes) from _Giovanni Resta_, May 01 2016