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 A071547 #2 Mar 30 2012 17:30:44
%S A071547 0,-1,2,0,-2,3,8,-259,-9006,37575,1988916,41615129,-444915500,
%T A071547 4752358604,-50506657344,532544416084,-4450492081868,-10234691885873,
%U A071547 241215169689690,21696729746925312,123619114295636184,174381272189413488,-43909101832286346168,-439142701170244441024
%N A071547 Determinant of the n X n matrix whose element (i,j) equals f(|i-j|) where f(n) is the sum of middle divisors (A071090).
%t A071547 f[n_] := If[n > 0, Plus @@ Select[Divisors[n], Sqrt[n/2] <= # < Sqrt[n*2] &], 0]; Table[ Det[ Table[ f[ Abs[i - j]], {i, 1, n}, {j, 1, n}]], {n, 1, 25}]
%Y A071547 Cf. A071090.
%K A071547 sign
%O A071547 1,3
%A A071547 _Robert G. Wilson v_, May 30 2002