

A221414


Number of nX3 arrays of occupancy after each element stays put or moves to some horizontal or antidiagonal neighbor, with every occupancy equal to zero or two


1



0, 10, 0, 150, 0, 2250, 0, 33750, 0, 506250, 0, 7593750, 0, 113906250, 0, 1708593750, 0, 25628906250, 0, 384433593750, 0, 5766503906250, 0, 86497558593750, 0, 1297463378906250, 0, 19461950683593750, 0, 291929260253906250, 0
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,2


COMMENTS



LINKS



FORMULA

Empirical: a(n) = 15*a(n2)


EXAMPLE

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


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



