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A296957
Number of n X 2 0..1 arrays with each 1 adjacent to 2, 3 or 5 king-move neighboring 1s.
1
1, 6, 16, 31, 96, 301, 801, 2261, 6746, 19456, 55751, 162436, 472621, 1368341, 3971361, 11541726, 33504416, 97254351, 282443176, 820183901, 2381405001, 6915014781, 20080097266, 58307232656, 169309052471, 491636470476
OFFSET
1,2
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) - 5*a(n-2) + 11*a(n-3) - 18*a(n-4) + 4*a(n-5).
Empirical g.f.: x*(1 + 2*x - 3*x^2 - 14*x^3 + 4*x^4) / (1 - 4*x + 5*x^2 - 11*x^3 + 18*x^4 - 4*x^5). - Colin Barker, Feb 25 2019
EXAMPLE
Some solutions for n=5:
..1..1. .1..1. .1..1. .1..0. .1..1. .0..0. .1..1. .0..0. .1..1. .0..0
..0..1. .0..1. .1..0. .1..1. .1..1. .0..0. .1..1. .0..0. .0..1. .1..1
..0..0. .0..1. .0..0. .0..0. .1..1. .0..0. .0..0. .0..0. .0..0. .1..1
..1..1. .1..1. .1..1. .1..1. .0..0. .1..1. .1..1. .0..0. .1..1. .0..0
..1..0. .0..1. .0..1. .1..1. .0..0. .1..1. .0..1. .0..0. .1..1. .0..0
CROSSREFS
Column 2 of A296963.
Sequence in context: A276917 A097118 A369548 * A341276 A301698 A301713
KEYWORD
nonn
AUTHOR
R. H. Hardin, Dec 22 2017
STATUS
approved