A027450 Third diagonal of A027446.

11, 13, 47, 37, 214, 365, 955, 847, 8372, 7602, 90510, 83490, 77484, 144573, 2303301, 2167165, 38878840, 36824788, 34977228, 33306468, 731129880, 699259470, 3350272926, 3215969526, 9276087128, 8931886700, 249757779700, 241131522060, 7225531873560

Offset: 3

Author

Olivier Gérard

Keywords

• nonn

Crossrefs

Cf. A027446.

Programs

Mathematica

rows = 31;
M = MatrixPower[Table[If[j <= i, 1/i, 0], {i, 1, rows}, {j, 1, rows}], 2];
T = Table[M[[n]]*LCM @@ Denominator[M[[n]]], {n, 1, rows}];
a[n_] := T[[n, n-2]];
Table[a[n], {n, 3, rows}] (* Jean-François Alcover, May 06 2022 *)

Formula

Numerators of sequence a[ n, n-2 ] in (a[ i, j ])^2 where a[ i, j ] = 1/i if j<=i, 0 if j>i.

Extensions

More terms from Sean A. Irvine, Nov 04 2019