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A183388 Half the number of n X 4 binary arrays with no element unequal to a strict majority of its king-move neighbors. 1
2, 2, 2, 4, 8, 16, 36, 74, 156, 334, 706, 1504, 3204, 6828, 14576, 31128, 66524, 142262, 304360, 651456, 1394894, 2987672, 6400950, 13716916, 29400542, 63027304, 135134330, 289772558, 621434722, 1332826866, 2858815828, 6132363430 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Column 4 of A183391.
LINKS
FORMULA
Empirical: a(n) = 2*a(n-1) + 2*a(n-2) - a(n-3) - 4*a(n-4) - 3*a(n-5) - a(n-6) - a(n-7) + 2*a(n-8) for n>9.
Empirical g.f.: 2*x*(1 - x - 3*x^2 - x^3 + 3*x^4 + 4*x^5 + 4*x^6 + 2*x^7 - 2*x^8) / (1 - 2*x - 2*x^2 + x^3 + 4*x^4 + 3*x^5 + x^6 + x^7 - 2*x^8). - Colin Barker, Mar 28 2018
EXAMPLE
Some solutions with a(1,1)=0 for 5 X 4:
..0..0..1..1....0..0..1..1....0..0..0..0....0..0..1..1....0..0..0..0
..0..0..1..1....0..0..1..1....0..0..0..0....0..0..1..1....0..0..0..0
..1..1..0..0....0..0..1..1....1..1..1..1....0..0..1..1....0..0..1..1
..1..1..0..0....0..0..1..1....1..1..1..1....1..1..0..0....1..1..1..1
..1..1..0..0....0..0..1..1....1..1..1..1....1..1..0..0....1..1..1..1
CROSSREFS
Cf. A183391.
Sequence in context: A285636 A102831 A262568 * A274076 A160179 A021822
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 04 2011
STATUS
approved

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Last modified April 22 01:34 EDT 2024. Contains 371887 sequences. (Running on oeis4.)