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A107445
Number of 4n X 4n alternating-sign matrices of type UU.
1
1, 5, 198, 63206, 163170556, 3410501048325, 577465332522075000, 792313244775191409073200, 8810729389390415079342840510816
OFFSET
0,2
LINKS
G. Kuperberg, Symmetry classes of alternating-sign matrices under one roof, arXiv:math/0008184 [math.CO], 2000-2001. [A_{UU}(4n)]
FORMULA
a(n) = A005156(n)*A059489(n).
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Zinn-Justin, May 16 2007, Jun 04 2007
STATUS
approved