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A231338 Number of (n+1) X (2+1) 0..3 arrays with no element unequal to a strict majority of its horizontal and vertical neighbors, with values 0..3 introduced in row major order. 1
4, 9, 22, 59, 159, 439, 1236, 3527, 10184, 29679, 87109, 257077, 761860, 2264909, 6749138, 20146867, 60218835, 180167387, 539423380, 1615890811, 4842424660, 14515699655, 43521570985, 130508409225, 391401045892, 1173929246129 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

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

Empirical g.f.: x*(4 - 11*x + x^2 - 5*x^3 + 10*x^4 + 2*x^5 + 3*x^6) / ((1 - x)*(1 - 3*x)*(1 + x + x^2)*(1 - 2*x - x^3)). - Colin Barker, Sep 28 2018

EXAMPLE

Some solutions for n=6:

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

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

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

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

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

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

..1..1..2....0..0..0....1..1..0....1..2..2....3..3..3....2..2..2....0..0..0

CROSSREFS

Column 2 of A231343.

Sequence in context: A122626 A135025 A231213 * A257272 A070713 A060250

Adjacent sequences:  A231335 A231336 A231337 * A231339 A231340 A231341

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 07 2013

STATUS

approved

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Last modified January 27 14:39 EST 2020. Contains 331295 sequences. (Running on oeis4.)