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A229574
Number of defective 4-colorings of an n X 4 0..3 array connected horizontally, vertically, diagonally and antidiagonally with exactly one mistake, and colors introduced in row-major 0..3 order.
1
6, 80, 171, 312, 568, 1064, 2064, 4120, 8384, 17256, 35728, 74168, 154080, 320008, 664112, 1376856, 2851456, 5898920, 12190416, 25166584, 51905312, 106955592, 220201840, 452985752, 931136448, 1912603624, 3925869584, 8053064760
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 6*a(n-1) - 13*a(n-2) + 12*a(n-3) - 4*a(n-4) for n>7.
Empirical g.f.: x*(6 + 44*x - 231*x^2 + 254*x^3 - 17*x^4 - 20*x^5 + 4*x^6) / ((1 - x)^2*(1 - 2*x)^2). - Colin Barker, Sep 19 2018
EXAMPLE
Some solutions for n=3:
..0..1..0..2....0..1..0..2....0..1..0..1....0..1..0..2....0..1..2..0
..3..2..3..1....3..2..3..3....2..3..2..3....3..2..3..1....2..3..1..3
..1..0..3..0....0..1..0..1....1..0..2..0....3..1..0..2....1..0..2..0
CROSSREFS
Column 4 of A229578.
Sequence in context: A024082 A132547 A248530 * A240409 A275137 A167570
KEYWORD
nonn
AUTHOR
R. H. Hardin, Sep 26 2013
STATUS
approved