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A203095 Number of n X 2 0..3 arrays with every nonzero element less than or equal to some horizontal or vertical neighbor. 1
4, 84, 1080, 12260, 143510, 1705124, 20174774, 238288768, 2816078514, 33286887866, 393430889634, 4650009454296, 54959608405434, 649582808767618, 7677588567818968, 90743395882037312, 1072519744806185004 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A203101.

LINKS

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

FORMULA

Empirical: a(n) = 10*a(n-1) -a(n-2) +236*a(n-3) +270*a(n-4) +945*a(n-5) +532*a(n-6) +576*a(n-7).

Empirical g.f.: 2*x*(2 + 22*x + 122*x^2 + 300*x^3 + 543*x^4 + 472*x^5 + 288*x^6) / (1 - 10*x + x^2 - 236*x^3 - 270*x^4 - 945*x^5 - 532*x^6 - 576*x^7). - Colin Barker, Jun 04 2018

EXAMPLE

Some solutions for n=5:

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

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

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

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

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

CROSSREFS

Cf. A203101.

Sequence in context: A282588 A178208 A069441 * A006344 A203244 A245544

Adjacent sequences:  A203092 A203093 A203094 * A203096 A203097 A203098

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 29 2011

STATUS

approved

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Last modified March 28 05:38 EDT 2020. Contains 333073 sequences. (Running on oeis4.)