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A188677
Primes p such that the minimum value of |p-2^x|, x>0, is also a prime.
1
11, 13, 19, 23, 29, 37, 43, 53, 59, 61, 67, 71, 83, 97, 109, 131, 139, 151, 157, 181, 197, 227, 233, 239, 251, 263, 269, 293, 317, 353, 359, 383, 409, 433, 439, 499, 509, 523, 541, 571, 601, 613, 619, 643, 661, 691, 709, 739, 751, 773, 797, 827, 857
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
Intersection of A086081 and A091932. - Robert G. Wilson v, May 27 2011
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
STATUS
approved