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A250846 Number of (n+1) X (1+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing min(x(i,j),x(i-1,j)) in the j direction. 1
100, 543, 2670, 12311, 54410, 233683, 983950, 4085631, 16796370, 68555723, 278351030, 1125823351, 4540620730, 18274604163, 73435058910, 294750719471, 1182035443490, 4737241699003, 18976271027590, 75987005717991 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 1 of A250853.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = 10*a(n-1) -35*a(n-2) +50*a(n-3) -24*a(n-4); a(n) = (832*4^n-846*3^n+204*2^n+2)/12.

G.f.: x*(100 - 457*x + 740*x^2 - 384*x^3) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)) (conjectured). - Colin Barker, Jan 18 2018

EXAMPLE

Some solutions for n=4

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

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

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

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

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

CROSSREFS

Sequence in context: A003588 A115695 A250700 * A172518 A174073 A231759

Adjacent sequences:  A250843 A250844 A250845 * A250847 A250848 A250849

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 28 2014

STATUS

approved

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Last modified August 10 16:56 EDT 2020. Contains 336381 sequences. (Running on oeis4.)