A188677 - OEIS

%I #19 Feb 12 2014 18:09:42

%S 11,13,19,23,29,37,43,53,59,61,67,71,83,97,109,131,139,151,157,181,

%T 197,227,233,239,251,263,269,293,317,353,359,383,409,433,439,499,509,

%U 523,541,571,601,613,619,643,661,691,709,739,751,773,797,827,857

%N Primes p such that the minimum value of |p-2^x|, x>0, is also a prime.

%C Originally submitted by _Benoit Cloitre_, Dec 17 2002 as A078686 and corrected by _Robert G. Wilson v_, Apr 08 2011.

%F Intersection of A086081 and A091932. - _Robert G. Wilson v_, May 27 2011

%t fQ[n_] := Block[{x = Floor@ Log2@ n}, PrimeQ@ Min[n - 2^x, 2^(x+1) - n]]; Select[ Prime@ Range@ 150, fQ] (* _Robert G. Wilson v_, Apr 08 2011 *)

%o (PARI) is(n)=if(isprime(n),my(x=log(n)\log(2));isprime(min(abs(n-1<<x),abs(n-2<<x))),0) \\ _Charles R Greathouse IV_, Jan 10 2013

%Y Cf. A078686, A086081, A091932.

%K nonn

%O 1,1

%A _Benoit Cloitre_ & _Robert G. Wilson v_, Apr 08 2011