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A267905 Number of n X 1 0..2 arrays with every repeated value in every row unequal to the previous repeated value, and in every column equal to the previous repeated value, and new values introduced in row-major sequential order. 1
1, 2, 5, 13, 34, 88, 225, 569, 1426, 3548, 8777, 21613, 53026, 129712, 316545, 770993, 1874914, 4553588, 11047625, 26779909, 64869586, 157043368, 380004897, 919150313, 2222499826, 5372538572, 12984354185, 31374801373, 75801065794 (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) = 5*a(n-1) -7*a(n-2) +a(n-3) +2*a(n-4).

Conjectures from Colin Barker, Jan 11 2019: (Start)

G.f.: x*(1 - 3*x + 2*x^2 + x^3) / ((1 - x)*(1 - 2*x)*(1 - 2*x - x^2)).

a(n) = ((1-sqrt(2))^(1+n) + (1+sqrt(2))^(1+n) - 2*(2^n-1)) / 4.

(End)

EXAMPLE

Some solutions for n=8:

..0....0....0....0....0....0....0....0....0....0....0....0....0....0....0....0

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

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

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

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

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

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

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

CROSSREFS

Column 1 of A267911.

Sequence in context: A318234 A027931 A218481 * A209230 A103142 A112844

Adjacent sequences: A267902 A267903 A267904 * A267906 A267907 A267908

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 22 2016

STATUS

approved

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Last modified January 30 02:40 EST 2023. Contains 359939 sequences. (Running on oeis4.)