A027449 Second diagonal of A027446.

3, 5, 7, 27, 22, 130, 225, 595, 532, 5292, 4830, 57750, 53460, 49764, 93093, 1486485, 1401400, 25185160, 23891868, 22724988, 21666840, 476166600, 455885430, 2186310126, 2100505176, 6063549800, 5842908500, 163495203300, 157949751960, 4735815444360

Offset

2,1

Links

Table of n, a(n) for n=2..31.

Formula

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

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-1]];
Table[a[n], {n, 2, rows}] (* Jean-François Alcover, May 06 2022 *)

Crossrefs

Cf. A027446.

Sequence in context: A362684 A294924 A249544 * A126670 A126669 A126668

Adjacent sequences: A027446 A027447 A027448 * A027450 A027451 A027452

Keyword

nonn

Author

Olivier Gérard

Extensions

More terms from Sean A. Irvine, Nov 04 2019

Status

approved