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A201375 T(n,k)=Number of nXk 0..1 arrays with rows and columns lexicographically nondecreasing read forwards, and nonincreasing read backwards 6
2, 2, 2, 2, 3, 2, 2, 4, 4, 2, 2, 5, 8, 5, 2, 2, 6, 14, 14, 6, 2, 2, 7, 22, 36, 22, 7, 2, 2, 8, 32, 80, 80, 32, 8, 2, 2, 9, 44, 157, 268, 157, 44, 9, 2, 2, 10, 58, 280, 786, 786, 280, 58, 10, 2, 2, 11, 74, 464, 2016, 3739, 2016, 464, 74, 11, 2, 2, 12, 92, 726, 4608, 15574, 15574, 4608 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Table starts

.2..2..2....2.....2......2........2.........2...........2............2

.2..3..4....5.....6......7........8.........9..........10...........11

.2..4..8...14....22.....32.......44........58..........74...........92

.2..5.14...36....80....157......280.......464.........726.........1085

.2..6.22...80...268....786.....2016......4608........9582........18446

.2..7.32..157...786...3739....15574.....55410......170616.......465037

.2..8.44..280..2016..15574...115168....728078.....3793342.....16517460

.2..9.58..464..4608..55410...728078...8866257....88486476....701948916

.2.10.74..726..9582.170616..3793342..88486476..1799674094..28852930912

.2.11.92.1085.18446.465037.16517460.701948916.28852930912.976134459840

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..220

EXAMPLE

Some solutions for n=7 k=5

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

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

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

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

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

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

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

CROSSREFS

Column 3 is A003682

Sequence in context: A127417 A308622 A198897 * A309865 A128764 A324818

Adjacent sequences:  A201372 A201373 A201374 * A201376 A201377 A201378

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Nov 30 2011

STATUS

approved

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Last modified January 24 21:49 EST 2022. Contains 350565 sequences. (Running on oeis4.)