A358812 Number of spanning trees in C_7 X C_n.

7, 799694, 7839321861, 40643137651228, 168437773747672835, 633426582213424399722, 2266101334892340404752384, 7871822605982542067643202616, 26818349084747196820449212376063, 90098172307754257628918141363625670, 299464785482715726798502702429093755197

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 7 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(7, n);