A358810 Number of spanning trees in C_5 X C_n.

5, 16810, 10609215, 4381392020, 1562500000000, 522217835532030, 168437773747672835, 53095647535975155240, 16463182598208445194045, 5040439500800000000000000, 1527650417538030913166754055, 459160235715332056282793308860

Offset: 1

Author

Seiichi Manyama, Dec 02 2022

Keywords

• nonn

Links

• Eric Weisstein's World of Mathematics, Spanning Tree
• Eric Weisstein's World of Mathematics, Torus Grid Graph

Crossrefs

Row 5 of A212796.

Programs

PARI

default(realprecision, 120);
T(n, k) = round(n*k*prod(a=1, n-1, prod(b=1, k-1, 4*sin(a*Pi/n)^2+4*sin(b*Pi/k)^2)));
a(n) = T(5, n);