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A183444 Number of n X 3 binary arrays with every 1 having exactly two king-move neighbors equal to 1. 2
1, 9, 18, 30, 107, 265, 553, 1505, 3852, 8922, 22477, 56889, 137617, 340401, 851098, 2091618, 5160851, 12817517, 31655009, 78159377, 193558964, 478614470, 1182673261, 2925763109, 7235864705, 17887850273, 44237338898, 109401520982 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A183450.

LINKS

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

FORMULA

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

Empirical g.f.: x*(1 + 7*x + x^2 - 5*x^3 - 2*x^5) / (1 - 2*x + x^2 - 8*x^3 + 7*x^4 - 2*x^5 + 2*x^6). - Colin Barker, Feb 27 2018

EXAMPLE

Some solutions for 5 X 3:

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

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

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

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

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

CROSSREFS

Cf. A183450.

Sequence in context: A044433 A161570 A140089 * A221533 A139591 A191268

Adjacent sequences:  A183441 A183442 A183443 * A183445 A183446 A183447

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 04 2011

STATUS

approved

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Last modified October 16 09:02 EDT 2021. Contains 348041 sequences. (Running on oeis4.)