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 A323254 #20 Dec 11 2019 02:19:53 %S A323254 1,7,58,614,8032,125757,2298208,48075148,1133554432,29756555315, %T A323254 860884417024,27218972906226,933850899349504,34556209025624041, %U A323254 1371957513591119872,58174957356247084568,2624017129323317493760,125454378698728779884895,6337442836338834419089408 %N A323254 The determinant of an n X n Toeplitz matrix M(n) whose first row consists of successive positive integer numbers 2*n - 1, n - 1, ..., 1 and whose first column consists of 2*n - 1, 2*n - 2, ..., n. %C A323254 The trace of the matrix M(n) is A000384(n). [Corrected by _Stefano Spezia_, Dec 08 2019] %C A323254 The sum of the first row of the matrix M(n) is A034856(n). %C A323254 The sum of the first column of the matrix M(n) is A000326(n). %C A323254 For n > 1, the sum of the superdiagonal of the matrix M(n) is A000290(n-1). %C A323254 For n > 1, the sum of the subdiagonal of the matrix M(n) is A001105(n-1). %H A323254 Vaclav Kotesovec, <a href="/A323254/b323254.txt">Table of n, a(n) for n = 1..300</a> %H A323254 Wikipedia, <a href="https://en.wikipedia.org/wiki/Toeplitz_matrix">Toeplitz matrix</a> %F A323254 a(n) ~ (5*exp(1) + exp(-1)) * n^n / 4. - _Vaclav Kotesovec_, Jan 10 2019 %e A323254 For n = 1 the matrix M(1) is %e A323254 1 %e A323254 with determinant Det(M(1)) = 1. %e A323254 For n = 2 the matrix M(2) is %e A323254 3, 1 %e A323254 2, 3 %e A323254 with Det(M(2)) = 7. %e A323254 For n = 3 the matrix M(3) is %e A323254 5, 2, 1 %e A323254 4, 5, 2 %e A323254 3, 4, 5 %e A323254 with Det(M(3)) = 58. %t A323254 b[i_]:=i; a[n_]:=Det[ToeplitzMatrix[Join[{b[2*n-1]}, Array[b, n-1, {2*n-2,n}]], Join[{b[2*n-1]},Array[b, n-1, {n-1,1}]]]]; Array[a,20] %o A323254 (PARI) tm(n) = {my(m = matrix(n, n, i, j, if (j==1, 2*n-i, n-j+1))); for (i=2, n, for (j=2, n, m[i, j] = m[i-1, j-1]; ); ); m;} %o A323254 a(n) = matdet(tm(n)); \\ _Stefano Spezia_, Dec 11 2019 %Y A323254 Cf. A000290, A000326, A000384, A001105, A001792. %Y A323254 Cf. A034856, A204235, A318173, A322908, A322909. %Y A323254 Cf. A323255 (permanent of matrix M(n)). %K A323254 nonn %O A323254 1,2 %A A323254 _Stefano Spezia_, Jan 09 2019