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Number of nX7 binary arrays with rows and columns lexicographically nondecreasing and column sums nondecreasing.
0

%I #3 Dec 29 2015 09:53:29

%S 8,92,1170,16585,251381,3889553,59155748,861030491,11809616668,

%T 151566391972,1816912772913,20365495779036

%N Number of nX7 binary arrays with rows and columns lexicographically nondecreasing and column sums nondecreasing.

%C Column 7 of A266428.

%e Some solutions for n=4

%e ..0..0..0..0..0..0..1....0..0..0..0..0..0..0....0..0..0..0..0..0..0

%e ..0..0..0..0..0..1..1....0..0..1..1..1..1..1....0..0..0..0..0..1..1

%e ..0..1..1..1..1..0..1....0..1..0..0..0..1..1....0..0..0..0..0..1..1

%e ..1..0..0..1..1..1..1....1..1..1..1..1..0..0....0..0..0..0..1..0..0

%Y Cf. A266428.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 29 2015