A183444 - OEIS

A183444

Number of n X 3 binary arrays with every 1 having exactly two king-move neighbors equal to 1.

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

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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 * A349417 A221533 A139591

Adjacent sequences: A183441 A183442 A183443 * A183445 A183446 A183447

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 04 2011

STATUS

approved