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 A140412 #13 Mar 04 2018 16:52:09
%S A140412 1,-12,864,-41472,24883200,21499084800,-50565847449600,
%T A140412 9708642710323200,-6291200476289433600,-45296643429283921920000,
%U A140412 657707262593202546278400000,2273036299522107999938150400000,-64536046616031690334243966156800000
%N A140412 Determinants of the n X n matrices whose (i,j)-elements are lcm(i^2, j^2).
%C A140412 The determinants of the n X n matrices whose (i,j)-elements are lcm(i,j) are given in A060238.
%F A140412 It appears that a(n) = Product_{k=1..n} MT2(k) * rad(k)^2 * mu(rad(k)), where MT2(k) is the k-th term of the Moebius transform of the sequence of squares, rad(k) is the squarefree kernel of k and mu denotes the Moebius function.
%o A140412 (PARI) a(n) = matdet(matrix(n, n, i, j, lcm(i^2, j^2))); \\ _Michel Marcus_, Jul 10 2014
%Y A140412 Cf. A060238.
%K A140412 sign
%O A140412 1,2
%A A140412 _John W. Layman_, Jun 17 2008