OFFSET
0,2
LINKS
A. J. Guttmann, Indicators of solvability for lattice models, Discrete Math., 217 (2000), 167-189 (chi_1 of Section 3).
I. Syozi and S. Naya, Symmetrical properties of two-dimensional Ising lattices, Prog. Theor. Phys., 24 (1960), 829-839.
FORMULA
G.f.: A(x, y)=(1-x^2)*(1-y^2)/(1-x-y-xy)^2 * (1 - 16*x^2*y^2/((1-x^2)^2*(1-y^2)^2))^(1/4).
EXAMPLE
Array begins:
1 2 2 2 2...
2 8 16 24 32...
2 16 48 104 180...
2 24 104 296 656...
2 32 180 656 1772...
CROSSREFS
KEYWORD
nonn,tabl
AUTHOR
Christian G. Bower, Jun 19 2000
STATUS
approved