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A162112
Number of n X n symmetric binary arrays with rows, considered as graycode numbers, in strictly increasing order, and no more than 4 ones in any row or column.
0
2, 4, 9, 56, 448, 5011, 63524, 940806, 15802494, 298218835, 6312264280, 147191591208, 3769342916158, 105162700003508
OFFSET
1,1
CROSSREFS
Sequence in context: A204428 A162111 A241600 * A162113 A162114 A162115
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jun 25 2009
STATUS
approved