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A180981 T(n,k)=number of nXk binary matrices with floor((n*k)/2) 1's and rows in lexicographically nonincreasing order and columns in lexicographically strictly increasing order 1
1, 1, 1, 0, 1, 1, 0, 1, 2, 1, 0, 0, 1, 2, 1, 0, 0, 1, 2, 3, 1, 0, 0, 0, 1, 3, 3, 1, 0, 0, 0, 1, 3, 5, 4, 1, 0, 0, 0, 0, 1, 5, 6, 4, 1, 0, 0, 0, 0, 1, 3, 8, 8, 5, 1, 0, 0, 0, 0, 0, 1, 6, 12, 10, 5, 1, 0, 0, 0, 0, 0, 1, 4, 12, 18, 13, 6, 1, 0, 0, 0, 0, 0, 0, 1, 8, 20, 24, 15, 6, 1, 0, 0, 0, 0, 0, 0, 1, 4, 18, 32, 33 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,9

COMMENTS

Table starts

.1.1..0..0...0...0...0...0...0...0..0..0.0.0

.1.1..1..0...0...0...0...0...0...0..0..0.0.0

.1.2..1..1...0...0...0...0...0...0..0..0.0.0

.1.2..2..1...1...0...0...0...0...0..0..0.0.0

.1.3..3..3...1...1...0...0...0...0..0..0.0.0

.1.3..5..5...3...1...1...0...0...0..0..0.0.0

.1.4..6..8...6...4...1...1...0...0..0..0.0.0

.1.4..8.12..12...8...4...1...1...0..0..0.0.0

.1.5.10.18..20..18..10...5...1...1..0..0.0.0

.1.5.13.24..32..32..24..13...5...1..1..0.0.0

.1.6.15.33..49..58..49..33..15...6..1..1.0.0

.1.6.18.43..73..94..94..73..43..18..6..1.1.0

.1.7.21.55.102.151.169.151.102..55.21..7.1.1

.1.7.25.69.141.227.289.289.227.141.69.25.7.1

LINKS

R. H. Hardin, Table of n, a(n) for n=1..365

EXAMPLE

All solutions for 6X3

..0..1..1....0..1..1....1..1..1....1..1..1....1..1..1

..0..1..1....0..1..1....0..1..1....0..1..1....1..1..1

..0..1..1....0..1..1....0..0..1....0..1..1....0..1..1

..0..0..1....0..1..1....0..0..1....0..0..1....0..0..1

..0..0..1....0..0..1....0..0..1....0..0..1....0..0..0

..0..0..1....0..0..0....0..0..1....0..0..0....0..0..0

CROSSREFS

Sequence in context: A257181 A164116 A164118 * A284317 A281243 A284314

Adjacent sequences:  A180978 A180979 A180980 * A180982 A180983 A180984

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Sep 30 2010

STATUS

approved

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Last modified July 27 15:29 EDT 2021. Contains 346307 sequences. (Running on oeis4.)