login
A204625
Number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock having unequal diagonal elements or unequal antidiagonal elements, and new values 0..2 introduced in row major order.
1
768, 43734, 2490558, 141832254, 8077061502, 459972403614, 26194503047262, 1491724252385406, 84950695233299262, 4837771196037723486, 275501337345598245918, 15689246928705157494846, 893471050128160321852158
OFFSET
1,1
COMMENTS
Column 3 of A204630.
LINKS
FORMULA
Empirical: a(n) = 60*a(n-1) - 175*a(n-2) + 68*a(n-3).
Empirical g.f.: 6*x*(128 - 391*x + 153*x^2) / (1 - 60*x + 175*x^2 - 68*x^3). - Colin Barker, Jun 07 2018
EXAMPLE
Some solutions for n=3:
..0..1..2..1....0..0..0..0....0..1..0..2....0..0..0..0....0..0..0..1
..2..2..0..0....1..0..1..0....1..2..2..1....1..0..1..0....2..0..1..1
..0..2..2..0....2..1..1..0....1..0..1..1....2..2..1..2....0..0..1..2
..0..1..0..1....2..0..0..0....0..0..2..0....0..0..2..0....2..0..0..1
CROSSREFS
Cf. A204630.
Sequence in context: A170783 A268970 A339763 * A290271 A206711 A308789
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 17 2012
STATUS
approved