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A250874 Number of (n+1) X (5+1) 0..3 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)+x(i-1,j) in the j direction. 1
2306, 11644, 55386, 250964, 1097986, 4685964, 19649066, 81358084, 333810066, 1360557884, 5518553146, 22303914804, 89906240546, 361699655404, 1453028599626, 5830816129124, 23379393301426, 93686006746524 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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) = (4112*4^n - 3915*3^n + 1080*2^n + 55)/3.

Empirical g.f.: 2*x*(1153 - 5708*x + 9828*x^2 - 5328*x^3) / ((1 - x)*(1 - 2*x)*(1 - 3*x)*(1 - 4*x)). - Colin Barker, Nov 22 2018

EXAMPLE

Some solutions for n=3:

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

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

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

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

CROSSREFS

Column 5 of A250877.

Sequence in context: A274578 A031774 A031546 * A247698 A247839 A280659

Adjacent sequences:  A250871 A250872 A250873 * A250875 A250876 A250877

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 28 2014

STATUS

approved

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Last modified October 23 01:49 EDT 2020. Contains 337962 sequences. (Running on oeis4.)