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A350296
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Minimum number of 1's in an n X n binary matrix with no zero 2 X 2 submatrix.
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4
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0, 1, 3, 7, 13, 20, 28, 40, 52, 66, 82, 99, 117, 140, 164, 189, 215, 243, 273, 304, 336, 376, 414, 454
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listen;
history;
text;
internal format)
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OFFSET
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1,3
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LINKS
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FORMULA
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EXAMPLE
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Solutions for a(3)=3, a(4)=7, a(5)=13), a(6)=20:
. . x . . . x . . . . x . . . x x x
. x . . x x . . x x x . . x x . . x
x . . x . x . x . x x . x . x . x .
x x . . x x . x . x x . x . .
x x x . . . x x x x .
x . x x . x
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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