%I #12 Sep 18 2022 11:38:13
%S 1,12,57,245,1005,4063,16327,65435,261965,1048259,4193742,16776218,
%T 67107091,268432305,1073736223,4294957340,17179851485,68719445272,
%U 274877851009,1099511528337,4398046334325,17592185730143,70368743618958,281474975717403,1125899905076842
%N Bisection of A013697.
%F a(n) = floor(1/(zeta(2n)-1)).
%K nonn
%O 1,2
%A _N. J. A. Sloane_, May 13 2011