A201375 T(n,k)=Number of nXk 0..1 arrays with rows and columns lexicographically nondecreasing read forwards, and nonincreasing read backwards.

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

Offset: 1

Author

R. H. Hardin Nov 30 2011

Keywords

• nonn
• tabl

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

Examples

			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
		

Links

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

Crossrefs

Column 3 is A003682