A027451 First diagonal of A027447.

1, 1, 4, 9, 144, 100, 3600, 11025, 78400, 63504, 6350400, 5336100, 768398400, 662547600, 577152576, 2029052025, 519437318400, 463325262400, 150117385017600, 135480939978384, 122885206329600, 111967718990400, 54192375991353600, 49770428644836900

Offset

1,3

Comments

Equals the denominators of MN(z;n)/(n!)^2 for n =>1, see A162990. - Johannes W. Meijer, Jul 21 2009

It appears that a(n) = denominator of n^2*sum(1/k^2,k=1..n). - Gary Detlefs, May 29 2010

Links

Table of n, a(n) for n=1..24.

Formula

Numerators of sequence a[ n, n ] in (a[ i, j ])^3 where a[ i, j ] = 1/i if j<=i, 0 if j>i.

a(n) = (lcm($1..n)/n)^2. - Johannes W. Meijer, Jul 21 2009

Mathematica

a[n_] := (LCM @@ Range[n]/n)^2; Table[a[n], {n, 1, 20}] (* Jean-François Alcover, Mar 05 2013, after Johannes W. Meijer *)

Crossrefs

From Johannes W. Meijer, Jul 21 2009: (Start)

Equals A002944(n)^2.

Equals A001044(n-1)/A025527(n)^2.

(End)

Sequence in context: A267898 A324981 A128524 * A227744 A035127 A354078

Adjacent sequences: A027448 A027449 A027450 * A027452 A027453 A027454

Keyword

nonn

Author

Olivier Gérard

Extensions

More terms from Sean A. Irvine, Nov 04 2019

Status

approved