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A189154
Number of n X 2 binary arrays without the pattern 0 0 1 1 diagonally, vertically or horizontally
2
4, 16, 64, 225, 784, 2704, 9216, 31329, 106276, 360000, 1218816, 4124961, 13957696, 47224384, 159769600, 540516001, 1828588644, 6186137104, 20927672896, 70798034241, 239508444816, 810252019600, 2741064339456, 9272956793409
OFFSET
1,1
COMMENTS
Column 2 of A189161.
LINKS
FORMULA
a(n) = A008937(n+1)^2.
Empirical: a(n) = 4*a(n-1) - a(n-2) - 14*a(n-4) + 4*a(n-5) + 2*a(n-6) + 8*a(n-7) - a(n-8) - a(n-10).
Empirical g.f.: x*(4 + 4*x^2 - 15*x^3 + 4*x^4 + x^5 + 8*x^6 - x^7 - x^9) / ((1 - x)*(1 + x + x^2 - x^3)*(1 - x - x^2 - x^3)*(1 - 3*x - x^2 - x^3)). - Colin Barker, Feb 28 2018
EXAMPLE
Some solutions for 4 X 2:
1 0 1 0 0 1 1 1 0 1 1 0 1 1 1 1 0 0 1 1
1 0 1 1 1 0 0 1 1 1 1 1 0 1 1 0 1 1 0 0
0 1 1 1 1 1 1 0 1 1 1 1 1 1 0 0 1 0 1 1
1 0 0 0 0 0 0 0 1 0 0 1 0 0 1 1 0 1 0 0
CROSSREFS
Sequence in context: A343200 A227312 A267729 * A189336 A262334 A065738
KEYWORD
nonn
AUTHOR
R. H. Hardin, Apr 17 2011
STATUS
approved