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A260363
Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00000011 or 00001111.
1
48, 78, 208, 436, 616, 1378, 2880, 4904, 9776, 19458, 35928, 70096, 136184, 257558, 498984, 963740, 1839600, 3547926, 6837184, 13109580, 25236616, 48572826, 93304016, 179507232, 345319152, 663776330, 1276734024, 2455611208, 4721490968
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = a(n-1) - a(n-2) + 5*a(n-3) - a(n-4) + 5*a(n-5) - 3*a(n-6) - a(n-7).
Empirical g.f.: 2*x*(24 + 15*x + 89*x^2 + 33*x^3 + 23*x^4 - 2*x^5 - 50*x^6) / (1 - x + x^2 - 5*x^3 + x^4 - 5*x^5 + 3*x^6 + x^7). - Colin Barker, Dec 29 2018
EXAMPLE
Some solutions for n=4:
..0..0..0....0..0..1....1..1..0....1..1..1....0..0..1....0..0..0....0..0..0
..0..0..0....0..1..0....0..1..0....0..0..1....0..0..1....0..1..1....0..0..1
..1..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..0..0....0..0..0....0..0..0....0..0..0
..0..0..0....0..1..0....0..1..1....0..1..0....1..1..0....1..0..0....0..0..0
..1..1..0....0..1..1....0..0..0....0..1..0....1..0..0....1..1..1....0..1..0
CROSSREFS
Column 1 of A260370.
Sequence in context: A261709 A261704 A260370 * A261553 A335281 A335196
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jul 23 2015
STATUS
approved