A347281 a(n) = 2^(n - 1)*permanent(M_n)^2 where M_n is the n X n matrix M_n(j, k) = cos(Pi*j*k/n).

1, 2, 4, 0, 36, 288, 144, 18432, 11664, 115200, 144400, 0, 808151184, 133693952, 262440000, 299649466368, 7937314520976, 73575242956800, 21204146201616, 6459752448000000, 212406372892224, 8753824001424826368, 195844025123172289600, 152252829159294763008, 26487254903393025000000

Offset: 1

Author

Hugo Pfoertner, Sep 18 2021

Keywords

• nonn

Examples

			a(7) = -3384288*cos(Pi/7) - 3460896*sin(Pi/14) - 45888*cos(2*Pi/7) - 28224*cos(15*Pi/7) + 48384*cos(17*Pi/7) + 1706400 + 3458400*sin(3*Pi/14) = 144. - _Chai Wah Wu_, Sep 19 2021
		

Crossrefs

Cf. A085524, A085530, A000169, A085527, A347929.

Programs

PARI

P(n)=matpermanent(matrix(n,n,j,k,cos((Pi*j*k)/n)));
for(k=1,25,print1(round(2^(k-1)*P(k)^2),", "))