%N Number of even formally self-dual (but not self-dual) binary codes of length 2n that have the highest possible minimal distance.
%H W. C. Huffman, <a href="https://doi.org/10.1016/j.ffa.2005.05.012">On the classification and enumeration of self-dual codes</a>, Finite Fields Applic., 11 (2005), 451-490.
%A _N. J. A. Sloane_, Sep 19 2005