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A194535
Number of lower triangles of an n X n 0..3 array with new values introduced in row major order 0..3 and no element equal to more than one horizontal or vertical neighbor
1
1, 4, 116, 16556, 7721920, 11525456507, 54979732214116, 838387866908847478, 40866499579695484000499, 6367568042830726931523028453, 3171485572844765112503023656979959
OFFSET
1,2
COMMENTS
Column 3 of A194540
LINKS
EXAMPLE
Some solutions for 3X3
..0......0......0......0......0......0......0......0......0......0......0
..1.2....1.1....1.2....1.2....1.1....1.2....1.2....1.2....1.0....1.2....1.1
..3.3.0..0.0.2..2.3.1..0.3.0..2.0.1..3.2.1..0.3.1..2.1.3..2.1.2..2.0.1..2.2.1
CROSSREFS
Sequence in context: A206689 A198080 A272158 * A030255 A146508 A374676
KEYWORD
nonn
AUTHOR
R. H. Hardin Aug 28 2011
STATUS
approved