A178842 a(n) = binomial((n-1)^2, n).

0, 0, 4, 126, 4368, 177100, 8347680, 450978066, 27540584512, 1878392407320, 141629804643600, 11703541346076580, 1052134368066259632, 102250849636865496528, 10683770265451303535424, 1194448077521704400002650, 142288257910903254700704000, 17993390003427864738863790640

Offset: 1

Author

Thomas Young, Jun 17 2010

Keywords

• nonn

Comments

Number of ways to place n objects in an (n-1) X (n-1) array (e.g., the number of ways to arrange stars in a flag's field pattern).

Links

• G. C. Greubel, Table of n, a(n) for n = 1..250

Crossrefs

Cf. A014062 (binomial(n^2, n)).

Programs

GAP

List([1..20], n -> Binomial((n-1)^2, n)); # G. C. Greubel, Jan 21 2019

Magma

[Binomial((n-1)^2,n): n in [1..20]]; // G. C. Greubel, Jan 21 2019

Mathematica

a[n_] := Binomial[(n - 1)^2, n]; Array[a, 18] (* Robert G. Wilson v, Jul 25 2010 *)

PARI

vector(20, n, binomial((n-1)^2,n)) \\ G. C. Greubel, Jan 21 2019

Sage

[binomial((n-1)^2,n) for n in (1..20)] # G. C. Greubel, Jan 21 2019