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A208404
Number of n X 4 0..3 arrays with new values 0..3 introduced in row major order and no element equal to more than two of its immediate leftward or upward or right-upward antidiagonal neighbors.
1
15, 2698, 658450, 163422914, 40595679634, 10084768380770, 2505261257850802, 622357842865595522, 154606345205565641170, 38407360426219085921186, 9541169432411414821885426, 2370220528768971149166621890
OFFSET
1,1
COMMENTS
Column 4 of A208408.
LINKS
FORMULA
Empirical: a(n) = 262*a(n-1) - 3385*a(n-2) + 2868*a(n-3) - 576*a(n-4) for n>5.
Empirical g.f.: x*(15 - 1232*x + 2349*x^2 - 1276*x^3 + 192*x^4) / ((1 - 13*x + 4*x^2)*(1 - 249*x + 144*x^2)). - Colin Barker, Jul 02 2018
EXAMPLE
Some solutions for n=4
..0..0..1..2....0..1..0..0....0..0..0..1....0..1..1..1....0..0..0..1
..0..3..3..0....2..0..3..0....1..2..1..1....0..0..0..1....1..0..1..1
..1..0..1..2....2..0..3..1....0..2..0..3....0..1..0..0....2..2..1..0
..1..1..0..0....1..2..0..2....0..0..2..1....0..1..1..1....0..3..0..0
CROSSREFS
Cf. A208408.
Sequence in context: A340185 A208197 A232407 * A208411 A249965 A108281
KEYWORD
nonn
AUTHOR
R. H. Hardin, Feb 26 2012
STATUS
approved