%I A054759
%S A054759 4,18,148,2970,143224,16448400,4484823396,2901094068042,
%T A054759 4448410550095612,16178049740086515288,139402641051212392498528,
%U A054759 2849295959501939989625992464,137950545200232788276834783781648
%N A054759 Number of Eulerian orientations of the n X n square lattice (with wrap-around), 
               i.e. number of arrow configurations on n X n grid that satisfy the 
               square ice rule.
%D A054759 S. R. Finch, Mathematical Constants, Cambridge, 2003, pp. 412-416.
%D A054759 Computed by Jennifer Henry in Dec. 1998.
%D A054759 E. H. Lieb, The residual entropy of square ice, Phys. Rev. 162 (1967) 
               162-172
%H A054759 S. R. Finch, <a href="http://algo.inria.fr/bsolve/constant/ice/ice.html">
               Lieb's Square Ice Constant</a>
%F A054759 Elliot Lieb proved that lim (a(n))^(1/n^2)=(4/3)^(3/2) as n->infinity.
%Y A054759 Sequence in context: A143992 A060841 A059837 this_sequence A007153 A156870 
               A145075
%Y A054759 Adjacent sequences: A054756 A054757 A054758 this_sequence A054760 A054761 
               A054762
%K A054759 nonn
%O A054759 1,1
%A A054759 S. R. Finch (Steven.Finch(AT)inria.fr), Apr 25 2000