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A228504
Number of n X 6 binary arrays with top left value 1 and no two ones adjacent horizontally, vertically, diagonally or antidiagonally.
1
8, 21, 239, 1252, 9528, 59839, 413786, 2724191, 18387032, 122539084, 821945828, 5495164996, 36800032261, 246231184011, 1648269251345, 11031030456148, 73833534042745, 494158034052549, 3307432804186754, 22136531409536410
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 3*a(n-1) + 30*a(n-2) - 17*a(n-3) - 138*a(n-4) + 85*a(n-5) + 116*a(n-6) - 42*a(n-7) - 32*a(n-8).
Empirical g.f.: x*(8 - 3*x - 64*x^2 + 41*x^3 + 63*x^4 - 24*x^5 - 18*x^6) / (1 - 3*x - 30*x^2 + 17*x^3 + 138*x^4 - 85*x^5 - 116*x^6 + 42*x^7 + 32*x^8). - Colin Barker, Sep 12 2018
EXAMPLE
Some solutions for n=4:
..1..0..0..1..0..0....1..0..0..0..0..0....1..0..0..1..0..1....1..0..0..1..0..0
..0..0..0..0..0..1....0..0..0..0..0..1....0..0..0..0..0..0....0..0..0..0..0..1
..0..1..0..0..0..0....0..0..0..0..0..0....1..0..0..0..0..0....0..0..0..1..0..0
..0..0..0..0..0..0....1..0..1..0..0..1....0..0..0..0..1..0....0..1..0..0..0..0
CROSSREFS
Column 6 of A228506.
Sequence in context: A240648 A231525 A228756 * A270552 A156239 A141369
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 23 2013
STATUS
approved