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

3,1

Links

Table of n, a(n) for n=3..31.

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.

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 *)

Crossrefs

Cf. A027446.

Sequence in context: A023268 A154292 A188386 * A234799 A036295 A132201

Adjacent sequences: A027447 A027448 A027449 * A027451 A027452 A027453

Keyword

nonn

Author

Olivier Gérard

Extensions

More terms from Sean A. Irvine, Nov 04 2019

Status

approved