%I #7 Dec 10 2016 22:37:33
%S -1,20,-560,20160,-887040,46126080,-2767564800,188194406400,
%T -14302774886400,1201433090457600,-110531844322099200,
%U 11053184432209920000,-1193743918678671360000,138474294566725877760000,-17170812526274008842240000
%N One-third of the even-indexed entries of A259056.
%C It is conjectured that this is an integer sequence.
%C For the odd-indexed entries of A259056 see
%C (-1)^(n-1)*A034976(n), n >= 1.
%F a(n) = A259056(2*n)/3, n >= 1.
%Y Cf. A034976, A259056.
%K sign,easy
%O 1,2
%A _Wolfdieter Lang_, Jul 07 2015