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A259888
Number of (n+2) X (2+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000000 00000001 or 00000011.
1
67, 174, 653, 1853, 4662, 13704, 40955, 114098, 320200, 925820, 2650721, 7507059, 21402747, 61226147, 174506650, 497034443, 1418169080, 4046094873, 11534896627, 32891041296, 93814175452, 267543153907, 762917347904, 2175699989264
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) - 3*a(n-2) + 11*a(n-3) - 8*a(n-4) - 5*a(n-5) - 5*a(n-6) - 2*a(n-7) + 3*a(n-8).
Empirical g.f.: x*(67 - 27*x + 332*x^2 - 321*x^3 - 316*x^4 - 179*x^5 - 125*x^6 + 156*x^7) / (1 - 3*x + 3*x^2 - 11*x^3 + 8*x^4 + 5*x^5 + 5*x^6 + 2*x^7 - 3*x^8). - Colin Barker, Dec 27 2018
EXAMPLE
Some solutions for n=4:
..1..0..0..1....0..0..0..1....1..1..0..0....0..0..0..0....1..0..0..1
..0..0..0..1....0..0..0..1....0..0..0..0....1..0..0..1....1..0..0..0
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..0..0..0..0....0..0..0..0....1..0..0..0....0..0..0..0....0..0..0..1
..1..0..0..1....0..1..0..0....1..0..0..1....1..0..0..1....0..0..0..1
..1..0..0..1....1..1..0..0....0..0..0..1....0..0..0..1....0..0..0..0
CROSSREFS
Column 2 of A259894.
Sequence in context: A199824 A341278 A142544 * A142671 A144326 A119593
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 07 2015
STATUS
approved