A358814 Number of spanning trees in C_9 X C_n.

9, 34928082, 5312031978672, 344499209234302500, 16463182598208445194045, 687776414074843514847584256, 26818349084747196820449212376063, 1005049441217682470864686231147005000, 36735015407753190053984060991247792275456

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 9 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(9, n);