A270446 Positive even numbers which are neither of the form p + 2^m + 1 nor of the form p + 2^m - 1 with p prime.

906, 3342, 3432, 4152, 4812, 4842, 5730, 7388, 7812, 8922, 10236, 10512, 11082, 11436, 12372, 12732, 13092, 14022, 14142, 14382, 14532, 15042, 15120, 16026, 16866, 17370, 18210, 18612, 18896, 18898, 20142, 20322, 20382, 20652, 21672, 24132, 24432, 24462

Offset

1,1

Comments

Numbers whose distance to both nearest neighbor de Polignac numbers is 1.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Maple

filter:= proc(n) local m;
   for m from 1 while n - 2^m > 0 do
     if isprime(n - 2^m + 1) or isprime(n - 2^m-1) then return false fi
   od;
   true
end proc:
select(filter, [seq(i, i=4..30000, 2)]); # Robert Israel, Mar 22 2016

Prog

(Magma) lst:=[]; for n in [2..24462 by 2] do t:=Floor(Log(2, n)); c:=0; m:=0; while m le t do a:=n-2^m; if IsPrime(a+1) or IsPrime(a-1) then break; end if; c+:=1; m+:=1; end while; if c eq t+1 then Append(~lst, n); end if; end for; lst;

Crossrefs

Cf. A006285.

Sequence in context: A330303 A181257 A235242 * A006917 A174862 A350852

Adjacent sequences: A270443 A270444 A270445 * A270447 A270448 A270449

Keyword

nonn

Author

Arkadiusz Wesolowski, Mar 17 2016

Status

approved