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 A027451 #19 Nov 04 2019 20:39:41
%S A027451 1,1,4,9,144,100,3600,11025,78400,63504,6350400,5336100,768398400,
%T A027451 662547600,577152576,2029052025,519437318400,463325262400,
%U A027451 150117385017600,135480939978384,122885206329600,111967718990400,54192375991353600,49770428644836900
%N A027451 First diagonal of A027447.
%C A027451 Equals the denominators of MN(z;n)/(n!)^2 for n =>1, see A162990. - _Johannes W. Meijer_, Jul 21 2009
%C A027451 It appears that a(n) = denominator of n^2*sum(1/k^2,k=1..n). - _Gary Detlefs_, May 29 2010
%F A027451 Numerators of sequence a[ n, n ] in (a[ i, j ])^3 where a[ i, j ] = 1/i if j<=i, 0 if j>i.
%F A027451 a(n) = (lcm($1..n)/n)^2. - _Johannes W. Meijer_, Jul 21 2009
%t A027451 a[n_] := (LCM @@ Range[n]/n)^2; Table[a[n], {n, 1, 20}] (* _Jean-François Alcover_, Mar 05 2013, after _Johannes W. Meijer_ *)
%Y A027451 From _Johannes W. Meijer_, Jul 21 2009: (Start)
%Y A027451 Equals A002944(n)^2.
%Y A027451 Equals A001044(n-1)/A025527(n)^2.
%Y A027451 (End)
%K A027451 nonn
%O A027451 1,3
%A A027451 _Olivier Gérard_
%E A027451 More terms from _Sean A. Irvine_, Nov 04 2019