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 A351984 #8 Mar 13 2022 18:56:39 %S A351984 1,2,6,24,120,840,5040 %N A351984 a(n) is the number of symmetric anti-Hadamard matrices of order n whose sum of the inverse squares of their singular values is maximal. %C A351984 The sequence of the ratio a(n+1)/a(n) begins with 2, 3, 4, 5, 7, 6, ... %C A351984 Is a(n+1)/a(n) integer for all n? If that is true, excluding the number 1, is the sequence of the ratio a(n+1)/a(n) a permutation of all other natural numbers? %H A351984 R. L. Graham and N. J. A. Sloane, <a href="http://dx.doi.org/10.1016/0024-3795(84)90090-9">Anti-Hadamard matrices</a>, Linear Alg. Applic., 62 (1984), 113-137. %Y A351984 Cf. A005312, A005313, A119002, A351153. %K A351984 nonn,hard,more %O A351984 1,2 %A A351984 _Stefano Spezia_, Feb 27 2022