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A172616
Number of 9*n X 2*n 0..1 arrays with row sums 2 and column sums 9.
1
1, 842090474940, 9561215418596022668009737500, 41499275921837441873503310658937755719615400000, 15806556884633733578544972910460376919497070823113887278535399000000
OFFSET
1,2
REFERENCES
Gao, Shanzhen, and Matheis, Kenneth, Closed formulas and integer sequences arising from the enumeration of (0,1)-matrices with row sum two and some constant column sums. In Proceedings of the Forty-First Southeastern International Conference on Combinatorics, Graph Theory and Computing. Congr. Numer. 202 (2010), 45-53.
LINKS
CROSSREFS
Sequence in context: A323533 A233800 A162027 * A233487 A297354 A172798
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 06 2010
EXTENSIONS
Incorrect formula removed by Jon E. Schoenfield, Jan 22 2018
STATUS
approved