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A278778 T(n,k)=Number of nXk 0..1 arrays with rows in nondecreasing lexicographic order and columns in nonincreasing lexicographic order, but with exactly two mistakes. 8
0, 0, 0, 0, 2, 0, 1, 20, 20, 1, 6, 117, 266, 117, 6, 21, 503, 1972, 1972, 503, 21, 56, 1750, 10784, 19750, 10784, 1750, 56, 126, 5209, 48501, 150085, 150085, 48501, 5209, 126, 252, 13751, 189595, 955347, 1673658, 955347, 189595, 13751, 252, 462, 33000 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,5

COMMENTS

Table starts

...0.....0.......0.........1...........6............21..............56

...0.....2......20.......117.........503..........1750............5209

...0....20.....266......1972.......10784.........48501..........189595

...1...117....1972.....19750......150085........955347.........5355983

...6...503...10784....150085.....1673658......16205001.......141166787

..21..1750...48501....955347....16205001.....251740932......3634987413

..56..5209..189595...5355983...141166787....3634987413.....90752836672

.126.13751..665212..27218249..1126917480...48847405083...2155380363189

.252.33000.2138149.127644118..8340736743..611199661843..48042054699217

.462.73282.6384894.559023840.57745890265.7140933364136.999491681597761

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..219

FORMULA

Empirical for column k:

k=1: a(n) = (1/120)*n^5 - (1/24)*n^4 + (1/24)*n^3 + (1/24)*n^2 - (1/20)*n

k=2: [polynomial of degree 10]

k=3: [polynomial of degree 19]

k=4: [polynomial of degree 36]

k=5: [polynomial of degree 69]

k=6: [polynomial of degree 134]

EXAMPLE

Some solutions for n=4 k=4

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

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

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

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

CROSSREFS

Column 1 is A000389(n+1).

Sequence in context: A267164 A158234 A270882 * A285931 A069845 A091397

Adjacent sequences:  A278775 A278776 A278777 * A278779 A278780 A278781

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin, Nov 28 2016

STATUS

approved

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Last modified April 26 08:16 EDT 2019. Contains 322472 sequences. (Running on oeis4.)