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A241073 Number of n X 2 0..2 arrays with no element equal to exactly one horizontal or vertical neighbor, with new values 0..2 introduced in row major order. 1
1, 4, 12, 39, 131, 444, 1516, 5195, 17847, 61424, 211672, 730119, 2520091, 8702628, 30063396, 103881123, 359017439, 1240945016, 4289745552, 14829991071, 51271047939, 177263517036, 612883590684, 2119068084731, 7326858673287 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

FORMULA

Empirical: a(n) = 6*a(n-1) - 8*a(n-2) - 4*a(n-3) + a(n-4) + 14*a(n-5) - 8*a(n-6) for n>7.

Empirical g.f.: x*(1 + x)*(1 - 3*x - x^2 + 4*x^3 + 4*x^4 - 4*x^5) / ((1 - x)*(1 - 5*x + 3*x^2 + 7*x^3 + 6*x^4 - 8*x^5)). - Colin Barker, Oct 29 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Column 2 of A241078.

Sequence in context: A308446 A334458 A122920 * A149328 A149329 A149330

Adjacent sequences:  A241070 A241071 A241072 * A241074 A241075 A241076

KEYWORD

nonn

AUTHOR

R. H. Hardin, Apr 15 2014

STATUS

approved

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Last modified June 30 09:38 EDT 2022. Contains 354920 sequences. (Running on oeis4.)