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 A374239 #12 Oct 10 2024 07:24:14
%S A374239 1,1,0,-1,1,-545,-13805,-301184,-18551951,-352513176,-31451535983,
%T A374239 -1209153784888,-87868166035113,-4204963833160760,-664087819207293468
%N A374239 a(n) is the minimal determinant of an n X n symmetric Toeplitz matrix having 1 on the main diagonal and all the integers 1, 2, ..., n-1 off-diagonal.
%H A374239 Lucas A. Brown, <a href="https://github.com/lucasaugustus/oeis/blob/main/A374239%2B40%2B41%2B42.py">Python program</a>.
%H A374239 Wikipedia, <a href="https://en.wikipedia.org/wiki/Toeplitz_matrix">Toeplitz Matrix</a>.
%e A374239 a(5) = -545:
%e A374239 [1, 1, 4, 2, 3]
%e A374239 [1, 1, 1, 4, 2]
%e A374239 [4, 1, 1, 1, 4]
%e A374239 [2, 4, 1, 1, 1]
%e A374239 [3, 2, 4, 1, 1]
%t A374239 a[0]=1; a[n_]:=Min[Table[Det[ToeplitzMatrix[Join[{1}, Part[Permutations[Range[n - 1]], i]]]], {i, (n-1)!}]]; Array[a, 11, 0]
%Y A374239 Cf. A350953, A374139.
%Y A374239 Cf. A374240 (maximal), A374241 (maximal absolute value), A374242 (minimal nonzero absolute value).
%K A374239 sign,hard,more
%O A374239 0,6
%A A374239 _Stefano Spezia_, Jul 01 2024
%E A374239 a(11)-a(14) from _Lucas A. Brown_, Oct 10 2024