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A201981 T(n,k)=Number of nXk 0..3 arrays with rows and columns lexicographically nondecreasing read forwards and nonincreasing read backwards 8
4, 4, 4, 4, 30, 4, 4, 72, 72, 4, 4, 131, 1372, 131, 4, 4, 208, 9260, 9260, 208, 4, 4, 304, 38112, 408599, 38112, 304, 4, 4, 420, 117744, 8002304, 8002304, 117744, 420, 4, 4, 557, 301612, 91893727, 858105364, 91893727, 301612, 557, 4, 4, 716, 676792 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Table starts

.4...4.......4...........4...............4..................4

.4..30......72.........131.............208................304

.4..72....1372........9260...........38112.............117744

.4.131....9260......408599.........8002304...........91893727

.4.208...38112.....8002304.......858105364........48452117136

.4.304..117744....91893727.....48452117136.....13486744809160

.4.420..301612...729771318...1706069013928...2238761872232964

.4.557..676792..4412536785..41801237632858.248685266018356303

.4.716.1375740.21616887220.764295988745248

.4.898.2589832.89573637672

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..97

FORMULA

Empirical: rows (and columns) 2,3,4,5 are polynomials of degree 3,6,18,30

EXAMPLE

Some solutions for n=5 k=3

..1..2..3....1..3..3....0..2..2....1..2..3....0..1..2....0..1..2....0..0..1

..2..0..3....2..1..3....2..1..2....2..0..3....1..0..2....2..1..1....1..3..0

..2..2..2....2..1..3....3..0..1....2..2..2....1..2..1....3..2..0....3..2..0

..3..0..1....3..0..3....3..2..0....3..3..0....2..1..1....3..2..0....3..2..0

..3..3..0....3..3..2....3..2..0....3..3..0....3..2..0....3..2..0....3..2..0

CROSSREFS

Sequence in context: A024727 A024552 A264768 * A199500 A164838 A059112

Adjacent sequences:  A201978 A201979 A201980 * A201982 A201983 A201984

KEYWORD

nonn,tabl

AUTHOR

R. H. Hardin Dec 07 2011

STATUS

approved

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Last modified November 13 19:25 EST 2018. Contains 317149 sequences. (Running on oeis4.)