%I A159299
%S A159299 0,0,0,0,288,166560,33539040,2350746720,75756999360,1388552614848,
%T A159299 16744788486720,146769785743680,1002373493948640,5606534724167520,
%U A159299 26640793339768608,110556058012152480,409297168707073920
%N A159299 Number of n-colorings of the 4 X 4 Sudoku graph.
%C A159299 The 4 X 4 Sudoku graph is a septic graph on 16 vertices and 56 edges. 
               a(n) gives the number of 4 X 4 Sudoku solutions, if each of up to 
               n numbers is allowed only once in every row, column and block.
%H A159299 Wikipedia "<a href="http://en.wikipedia.org/wiki/Mathematics_of_Sudoku">
               Mathematics of Sudoku</a>"
%H A159299 Weisstein, Eric W. "<a href="http://mathworld.wolfram.com/ChromaticPolynomial.html">
               Chromatic Polynomial</a>".
%H A159299 Timme, Marc; van Bussel, Frank; Fliegner, Denny; Stolzenberg, Sebastian 
               (2009) "Counting complex disordered states by efficient pattern matching: 
               chromatic polynomials and Potts partition functions", New J. Phys. 
               11 023001, doi: <a href="http://dx.doi.org/10.1088/1367-2630/11/2/
               023001">10.1088/1367-2630/11/2/023001</a>.
%F A159299 a(n) = n^16 -56*n^15 + ... (see Maple program).
%p A159299 a:= n-> n^16 -56*n^15 +1492*n^14 -25072*n^13 +296918*n^12 -2621552*n^11 
               +17795572*n^10 -94352168*n^9 +392779169*n^8 -1279118840*n^7 +3217758336*n^6 
               -6107865464*n^5 +8413745644*n^4 -7877463064*n^3 +4436831332*n^2 -1117762248*n: 
               seq (a(n), n=0..20);
%Y A159299 Sequence in context: A163007 A069329 A037946 this_sequence A047805 A008695 
               A107739
%Y A159299 Adjacent sequences: A159296 A159297 A159298 this_sequence A159300 A159301 
               A159302
%K A159299 nonn
%O A159299 0,5
%A A159299 Alois P. Heinz (heinz(AT)hs-heilbronn.de), Apr 09 2009