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A238838
Number of 2n X 2n addition squares in which every digram (s,s;), s' != s, appears once horizontally and once vertically.
1
2, 48, 5760, 5806080, 75246796800, 1780537083494400, 115939740156316876800, 19864514173849162481664000
OFFSET
1,1
LINKS
Gilbert, E. N., Latin squares which contain no repeated digrams, SIAM Rev. 7 1965 189--198. MR0179095 (31 #3346).
FORMULA
a(n) = (2*n)!*A141599(n)^2/phi(n).
CROSSREFS
KEYWORD
nonn,more
AUTHOR
N. J. A. Sloane, Mar 15 2014
STATUS
approved