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A280853 Number of n X 2 0..2 arrays with no element equal to more than one of its king-move neighbors and with new values introduced in order 0 sequentially upwards. 2
2, 9, 29, 110, 442, 1708, 6596, 25624, 99432, 385584, 1495696, 5802080, 22506144, 87301312, 338644032, 1313606016, 5095497344, 19765519104, 76670777600, 297407202816, 1153647430144, 4475017382912, 17358666073088, 67334551345152 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A280859.

LINKS

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

FORMULA

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

Empirical g.f.: x*(1 - x)*(2 + 3*x - 4*x^3) / (1 - 4*x + 2*x^2 - 8*x^3 + 8*x^4). - Colin Barker, Mar 22 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Cf. A280859.

Sequence in context: A351191 A241774 A183383 * A268568 A150902 A150903

Adjacent sequences:  A280850 A280851 A280852 * A280854 A280855 A280856

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 09 2017

STATUS

approved

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Last modified May 28 07:30 EDT 2022. Contains 354112 sequences. (Running on oeis4.)