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 A374389 #5 Jul 07 2024 13:48:57 %S A374389 4,24,116,192,1079,664,720,216 %N A374389 a(n) is the minimal absolute value of the determinant of a nonsingular n X n symmetric Toeplitz matrix having 0 on the main diagonal and all the first n-1 primes off-diagonal. %C A374389 The offset is 2 because for n = 1 the unique symmetric Toeplitz matrix is singular. %H A374389 Wikipedia, <a href="https://en.wikipedia.org/wiki/Toeplitz_matrix">Toeplitz Matrix</a>. %e A374389 a(5) = 192: %e A374389 [0, 5, 3, 2, 7] %e A374389 [5, 0, 5, 3, 2] %e A374389 [3, 5, 0, 5, 3] %e A374389 [2, 3, 5, 0, 5] %e A374389 [7, 2, 3, 5, 0] %t A374389 a[n_]:=Min[Select[Table[Abs[Det[ToeplitzMatrix[Join[{0},Part[Permutations[Prime[Range[n-1]]],i]]]]],{i,(n-1)!}],Positive]]; Array[a,8,2] %Y A374389 Cf. A374386 (minimal), A374387 (maximal), A374388 (maximal absolute value). %Y A374389 Cf. A374068 (minimal permanent), A374390 (maximal permanent). %K A374389 nonn,hard,more %O A374389 2,1 %A A374389 _Stefano Spezia_, Jul 07 2024