This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A048615 #21 Dec 17 2016 10:28:38
%S A048615 1,1,1,27,127,34603,278617,264156210586399
%N A048615 Numerator of mass (Sum 1/|Aut(H)|) of Hadamard matrices of order 4n.
%C A048615 This list starts with the Hadamard matrix of order 4. The masses of the Hadamard matrices of orders 1 and 2 are 1/2 and 1/8 respectively.
%H A048615 V. Alvarez, J. A. Armario, M. D. Frau and F. Gudiel, <a href="http://dx.doi.org/10.1016/j.laa.2011.05.018">The maximal determinant of cocyclic (-1, 1)-matrices over D_{2t}</a>, Linear Algebra and its Applications, 2011.
%H A048615 <a href="/index/Ha#Hadamard">Index entries for sequences related to Hadamard matrices</a>
%e A048615 1/192, 1/21504, 1/190080, 27/573440, 127/218880, 34603/40480, 278617/2106, 264156210586399/53329920, ...
%Y A048615 Cf. A048616, A007299, A036297.
%K A048615 frac,nonn,hard,nice
%O A048615 1,4
%A A048615 _N. J. A. Sloane_, E. M. Rains
%E A048615 a(8) from _Brendan McKay_, Feb 11 2012