A255967 Odd numbers n that are neither of the form p + 2^k nor of the form p - 2^k with 2^k < n, and p prime.

1, 1973, 3181, 3967, 4889, 5617, 7747, 7913, 8363, 8587, 8923, 11437, 11993, 12517, 13285, 13973, 14101, 14231, 14489, 16117, 16769, 16849, 18391, 18611, 19583, 19819, 21289, 21683, 21701, 21893, 22147, 22817, 22949, 23651, 24943, 25829, 27197, 27437

Offset

1,2

Comments

Odd n such that for all 2^k < n the numbers n + 2^k and n - 2^k are composite.

Links

Table of n, a(n) for n=1..38.

Prog

(Magma) lst:=[]; for n in [1..27437 by 2] do t:=0; k:=0; while 2^k lt n do if IsPrime(n-2^k) or IsPrime(n+2^k) then t:=1; break; end if; k+:=1; end while; if IsZero(t) then Append(~lst, n); end if; end for; lst;

Crossrefs

Cf. A076335.

Subsequence of A006285. Supersequence of A256163.

A153352 gives the primes.

Sequence in context: A205210 A183692 A206218 * A153352 A251816 A108386

Adjacent sequences: A255964 A255965 A255966 * A255968 A255969 A255970

Keyword

nonn

Author

Arkadiusz Wesolowski, Mar 12 2015

Status

approved