OFFSET
1,1
COMMENTS
Originally submitted by Benoit Cloitre, Dec 17 2002 as A078686 and corrected by Robert G. Wilson v, Apr 08 2011.
FORMULA
MATHEMATICA
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 *)
PROG
(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
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre & Robert G. Wilson v, Apr 08 2011
STATUS
approved