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A232150
Number of 2 X n 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally, diagonally or antidiagonally.
1
1, 23, 191, 1299, 9097, 65837, 474721, 3410799, 24510495, 176212555, 1266835473, 9107139805, 65470085209, 470658881191, 3383528394527, 24323895055139, 174862377541881, 1257070592095501, 9036972483506993, 64966018290364927
OFFSET
1,2
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) + 4*a(n-2) + 25*a(n-3) + 60*a(n-4) - 24*a(n-5) - 72*a(n-6).
Empirical g.f.: x*(1 + 17*x + 49*x^2 + 36*x^3 - 96*x^4 - 72*x^5) / (1 - 6*x - 4*x^2 - 25*x^3 - 60*x^4 + 24*x^5 + 72*x^6). - Colin Barker, Oct 03 2018
EXAMPLE
Some solutions for n=6.
..1..2..1..1..2..2....0..1..1..2..2..2....1..1..2..0..2..2....1..2..0..2..1..1
..2..0..0..0..1..2....0..1..2..2..2..2....1..2..2..1..1..0....2..1..2..1..2..2
CROSSREFS
Row 2 of A232149.
Sequence in context: A167467 A129052 A201859 * A269086 A160083 A140545
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 19 2013
STATUS
approved