A358813 - OEIS

%I #9 Dec 02 2022 13:10:24

%S 8,5326848,205683135000,3771854305099776,53095647535975155240,

%T 665880333340217184000000,7871822605982542067643202616,

%U 89927963805390785392395474173952,1005049441217682470864686231147005000

%N Number of spanning trees in C_8 X C_n.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/SpanningTree.html">Spanning Tree</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/TorusGridGraph.html">Torus Grid Graph</a>

%o (PARI) default(realprecision, 120);

%o 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)));

%o a(n) = T(8, n);

%Y Row 8 of A212796.

%K nonn

%O 1,1

%A _Seiichi Manyama_, Dec 02 2022