A027458 - OEIS

%I #12 May 06 2022 07:55:41

%S 2,7,47,57,459,1023,3349,3601,42131,44441,605453,631193,655217,

%T 1355479,23763863,24444543,476698557,488338185,499423545,510005025,

%U 11962908135,12186001005,62000850801,63030510201,192066102203,194934439103,5733412167187,5811048485947

%N Third column of A027446.

%F 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 rows = 30;

%t M = MatrixPower[Table[If[j <= i, 1/i, 0], {i, 1, rows}, {j, 1, rows}], 2];

%t T = Table[M[[n]]*LCM @@ Denominator[M[[n]]], {n, 1, rows}];

%t a[n_] := T[[n, 3]];

%t Table[a[n], {n, 3, rows}] (* _Jean-François Alcover_, May 06 2022 *)

%K nonn

%O 3,1

%A _Olivier Gérard_

%E More terms from _Sean A. Irvine_, Nov 04 2019