

A229505


Number of defective 3colorings of an n X 3 0..2 array connected diagonally and antidiagonally with exactly one mistake, and colors introduced in rowmajor 0..2 order.


1



0, 48, 480, 4032, 31104, 228096, 1617408, 11197440, 76142592, 510603264, 3386105856, 22251552768, 145118822400, 940369969152, 6060162023424, 38868625391616, 248257671856128, 1579821548175360, 10020582391283712
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OFFSET

1,2


COMMENTS



LINKS



FORMULA

Empirical: a(n) = 12*a(n1)  36*a(n2) for n>3.
G.f.: 48*x^2*(1  2*x) / (1  6*x)^2.
a(n) = 2^(2+n)*3^(n2)*(2*n  1) for n>1.
(End)


EXAMPLE

Some solutions for n=4
..0..0..1....0..1..2....0..1..1....0..1..0....0..1..2....0..1..0....0..1..0
..2..2..2....2..1..2....2..2..0....0..2..0....0..1..0....2..2..2....2..1..2
..0..1..1....0..1..0....0..1..1....1..1..0....1..1..2....1..0..0....1..0..2
..1..2..0....1..2..2....2..2..1....0..2..1....0..0..2....1..2..0....2..0..1


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



