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 A027458 #12 May 06 2022 07:55:41
%S A027458 2,7,47,57,459,1023,3349,3601,42131,44441,605453,631193,655217,
%T A027458 1355479,23763863,24444543,476698557,488338185,499423545,510005025,
%U A027458 11962908135,12186001005,62000850801,63030510201,192066102203,194934439103,5733412167187,5811048485947
%N A027458 Third column of A027446.
%F A027458 Numerators of sequence a[ 3, n ] in (a[ i, j ])^2 where a[ i, j ] = 1/i if j<=i, 0 if j>i
%t A027458 rows = 30;
%t A027458 M = MatrixPower[Table[If[j <= i, 1/i, 0], {i, 1, rows}, {j, 1, rows}], 2];
%t A027458 T = Table[M[[n]]*LCM @@ Denominator[M[[n]]], {n, 1, rows}];
%t A027458 a[n_] := T[[n, 3]];
%t A027458 Table[a[n], {n, 3, rows}] (* _Jean-François Alcover_, May 06 2022 *)
%K A027458 nonn
%O A027458 3,1
%A A027458 _Olivier Gérard_
%E A027458 More terms from _Sean A. Irvine_, Nov 04 2019