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A224033 Number of n X 3 0..1 arrays with antidiagonals unimodal and rows and diagonals nondecreasing. 1
4, 13, 37, 105, 298, 848, 2419, 6908, 19737, 56401, 161181, 460622, 1316360, 3761867, 10750568, 30722673, 87798365, 250907593, 717036338, 2049125344, 5855930115, 16734904820, 47824518777, 136671503209, 390575802373, 1116176041318 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 3 of A224038.

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) - 3*a(n-2) - a(n-3) + 2*a(n-5).

Empirical g.f.: x*(1 - x)*(4 + x - 2*x^2 - 2*x^3) / (1 - 4*x + 3*x^2 + x^3 - 2*x^5). - Colin Barker, Aug 26 2018

EXAMPLE

Some solutions for n=3:

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

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

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

CROSSREFS

Cf. A224038.

Sequence in context: A300985 A080145 A097551 * A095126 A077842 A067633

Adjacent sequences:  A224030 A224031 A224032 * A224034 A224035 A224036

KEYWORD

nonn

AUTHOR

R. H. Hardin, Mar 30 2013

STATUS

approved

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Last modified September 20 02:19 EDT 2021. Contains 347577 sequences. (Running on oeis4.)