login
A267725
Number of 2Xn arrays containing n copies of 0..2-1 with every element equal to at least one horizontal neighbor and the top left element equal to 0.
2
0, 1, 1, 3, 5, 12, 26, 60, 143, 353, 879, 2200, 5528, 13963, 35421, 90122, 229729, 586438, 1498966, 3836099, 9827905, 25202549, 64683193, 166137751, 427022480, 1098291533, 2826500851, 7278246356, 18751418071, 48334451894, 124647030884
OFFSET
1,4
COMMENTS
Row 2 of A267724.
LINKS
EXAMPLE
Some solutions for n=6
..0..0..1..1..0..0....0..0..1..1..1..1....0..0..1..1..0..0....0..0..0..0..0..0
..0..0..1..1..1..1....0..0..0..0..1..1....1..1..1..1..0..0....1..1..1..1..1..1
CROSSREFS
Cf. A267724.
Sequence in context: A017921 A280000 A241097 * A161762 A245649 A291035
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 20 2016
STATUS
approved