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A229406
Number of n X 2 0..3 arrays avoiding 11 horizontally, 22 vertically, 33 antidiagonally and 00 diagonally.
1
15, 163, 1756, 18712, 199595, 2127718, 22684613, 241841143, 2578301479, 27487534672, 293047669224, 3124213038091, 33307577031714, 355095715688893, 3785714221110283, 40359912854042611, 430281439964832908
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 10*a(n-1) + 13*a(n-2) - 67*a(n-3) + 38*a(n-4) - 2*a(n-5).
Empirical g.f.: x*(15 + 13*x - 69*x^2 + 38*x^3 - 2*x^4) / (1 - 10*x - 13*x^2 + 67*x^3 - 38*x^4 + 2*x^5). - Colin Barker, Sep 15 2018
EXAMPLE
Some solutions for n=3:
..3..3....3..2....2..3....3..3....1..0....0..2....1..0....1..0....0..2....3..3
..2..2....3..0....1..2....2..0....3..0....3..3....3..2....1..0....1..3....1..3
..1..0....0..1....1..3....3..3....3..0....1..2....2..3....3..1....2..0....0..1
CROSSREFS
Column 2 of A229412.
Sequence in context: A016243 A164599 A016291 * A118093 A167615 A210326
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 22 2013
STATUS
approved