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A183445 Number of n X 4 binary arrays with every 1 having exactly two king-move neighbors equal to 1. 1
1, 13, 30, 72, 283, 831, 2399, 7761, 23840, 72396, 225569, 696929, 2144537, 6635889, 20510002, 63318408, 195704391, 604826763, 1868678179, 5774848073, 17846507936, 55148861000, 170427655945, 526681961257, 1627610746225, 5029867948101 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 4 of A183450.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 3*a(n-1) + a(n-2) + 5*a(n-3) - 18*a(n-4) - 16*a(n-5) + 7*a(n-6) + 3*a(n-7) + a(n-8) - a(n-9).

Empirical g.f.: x*(1 + x)*(1 + 9*x - 19*x^2 - 17*x^3 + 7*x^4 + 3*x^5 + x^6 - x^7) / (1 - 3*x - x^2 - 5*x^3 + 18*x^4 + 16*x^5 - 7*x^6 - 3*x^7 - x^8 + x^9). - Colin Barker, Mar 29 2018

EXAMPLE

Some solutions for 5 X 4:

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

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

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

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

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

CROSSREFS

Cf. A183450.

Sequence in context: A139577 A172463 A329950 * A296124 A299130 A156532

Adjacent sequences:  A183442 A183443 A183444 * A183446 A183447 A183448

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 04 2011

STATUS

approved

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Last modified September 28 04:53 EDT 2021. Contains 347703 sequences. (Running on oeis4.)