OFFSET
1,2
LINKS
W.-J. Tzeng and F. Y. Wu, Spanning Trees on Hypercubic Lattices and Non-orientable Surfaces, arXiv:cond-mat/0001408 [cond-mat.stat-mech], 2000.
Eric Weisstein's World of Mathematics, Grid Graph
Eric Weisstein's World of Mathematics, Spanning Tree
FORMULA
a(n) = 2^(n^3-1) / n^3 * Product_{n1=0..n-1 n2=0..n-1 n3=0..n-1} (3- cos(Pi*n1/n) - cos(Pi*n2/n) - cos(Pi*n3/n) ) where n1, n2, n3 are not all 0.
Limit_{n->infinity} a(n)^(1/n^3) = exp(8 * A340322 / Pi^3) = 5.330202889205167421134597996649659520108446730592285502966091902480522584119... - Vaclav Kotesovec, Jan 05 2021
MATHEMATICA
Table[2^(n^3 - 1)/n^3 Product[Piecewise[{{1, i == j == k == 0}}, 3 - Cos[Pi i/n] - Cos[Pi j/n] - Cos[Pi k/n]], {i, 0, n - 1}, {j, 0, n - 1}, {k, 0, n - 1}], {n, 12}] // Round
CROSSREFS
KEYWORD
nonn
AUTHOR
Sharon Sela (sharonsela(AT)hotmail.com), Jun 04 2002
STATUS
approved