%N Number of doubly-regular tournaments of order 4n-1.
%C Equally, number of skew digraphs in switching classes of Hadamard matrices of order 4n.
%D Spence, Edward; Classification of Hadamard matrices of order 24 and 28. Discrete Math. 140 (1995), no. 1-3, 185-243.
%A _N. J. A. Sloane_.
%E Better name suggested by Brendan McKay, Oct 31 2007