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A281982
Number of n X 2 0..1 arrays with no element unequal to more than four of its king-move neighbors, with the exception of exactly one element, and with new values introduced in order 0 sequentially upwards.
1
0, 0, 2, 16, 88, 432, 2008, 8992, 39200, 167552, 705440, 2934784, 12091264, 49416448, 200598912, 809606656, 3251253760, 12999782400, 51779385856, 205542608896, 813446920192, 3210502631424, 12640023828480, 49653803819008
OFFSET
1,3
LINKS
FORMULA
Empirical: a(n) = 8*a(n-1) - 20*a(n-2) + 24*a(n-3) - 36*a(n-4) + 16*a(n-5) - 16*a(n-6).
Empirical g.f.: 2*x^3 / (1 - 4*x + 2*x^2 - 4*x^3)^2. - Colin Barker, Feb 20 2019
EXAMPLE
Some solutions for n=4:
..0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..0. .0..1. .0..0
..1..0. .1..1. .0..0. .0..0. .1..0. .0..1. .0..1. .1..0. .0..0. .0..1
..0..0. .1..0. .0..1. .1..0. .0..0. .0..0. .0..0. .0..0. .0..1. .0..0
..0..0. .1..1. .0..0. .0..0. .1..1. .0..0. .1..0. .0..1. .0..0. .0..1
CROSSREFS
Column 2 of A281988.
Sequence in context: A370192 A069440 A000431 * A207595 A253487 A207019
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 04 2017
STATUS
approved