%I A099112
%S A099112 6,73080,472598638512,1631619756904447290240,
%T A099112 3008692066440440678503082183460000,
%U A099112 2962701176869736970134706082584757742017500000000
%N A099112 Number of rhombus tilings of a hexagon with all sides of length 2n which 
               contain the rhombus above and next to the center of the hexagon.
%H A099112 M. Fulmek and C. Krattenthaler, <a href="http://arXiv.org/abs/math.CO/
               9909038">[math/9909038] The number of rhombus tilings of a symmetric 
               hexagon which contain a fixed rhombus on the symmetry axis, II</a>
%o A099112 (PARI) a(n)=(1/3-1/12*binomial(2*n,n)^3/binomial(6*n,3*n))*prod(i=1,2*n,
               prod(j=1,2*n,prod(k=1,2*n,(i+j+k-1)/(i+j+k-2))))
%Y A099112 Cf. A099112-A099117, A008793.
%Y A099112 Sequence in context: A076913 A101450 A101439 this_sequence A086897 A034208 
               A003834
%Y A099112 Adjacent sequences: A099109 A099110 A099111 this_sequence A099113 A099114 
               A099115
%K A099112 nonn
%O A099112 1,1
%A A099112 Ralf Stephan, Oct 01 2004