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A184224
Half the number of (n+1) X 3 0..3 arrays with every 2 X 2 subblock diagonal sum differing from its antidiagonal sum by more than 3.
1
57, 411, 2318, 14641, 88103, 541936, 3302001, 20204829, 123402988, 754319381, 4609217629, 28168842830, 172139309061, 1051973256999, 6428702835542, 39286618550317, 240084864227147, 1467186858794824, 8966146857909117
OFFSET
1,1
COMMENTS
Column 2 of A184231.
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) + 7*a(n-2) - 42*a(n-3) + 17*a(n-4) + 24*a(n-5) - 12*a(n-6).
Empirical g.f.: x*(57 + 69*x - 547*x^2 + 250*x^3 + 324*x^4 - 168*x^5) / (1 - 6*x - 7*x^2 + 42*x^3 - 17*x^4 - 24*x^5 + 12*x^6). - Colin Barker, Apr 12 2018
EXAMPLE
Some solutions for 5 X 3:
..0..1..0....3..0..3....0..3..0....2..0..3....2..3..0....3..0..2....2..0..3
..3..0..3....1..3..0....2..0..3....0..3..0....3..0..2....0..3..1....0..3..2
..2..3..1....3..1..3....1..3..0....3..0..2....1..3..1....3..0..3....1..0..3
..3..0..2....0..3..0....2..0..2....0..3..0....3..0..2....1..3..1....0..3..1
..1..3..1....3..1..3....1..3..1....2..0..1....0..2..0....2..0..3....2..0..2
CROSSREFS
Cf. A184231.
Sequence in context: A237360 A076459 A268260 * A337629 A218812 A290779
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 10 2011
STATUS
approved