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A267902
Number of 2Xn arrays containing n copies of 0..2-1 with every element equal to at least one horizontal or vertical neighbor and the top left element equal to 0.
1
0, 2, 3, 11, 29, 93, 268, 842, 2547, 7946, 24539, 76721, 239462, 751569, 2360679, 7437243, 23461543, 74155431, 234687456, 743792675, 2359972537, 7496293462, 23834595755, 75852059135, 241594260984, 770090455545, 2456436981617
OFFSET
1,2
COMMENTS
Row 2 of A267901.
LINKS
EXAMPLE
Some solutions for n=4
..0..1..0..1....0..0..1..1....0..1..1..1....0..0..1..0....0..0..0..1
..0..1..0..1....1..1..0..0....0..0..0..1....1..1..1..0....1..1..0..1
CROSSREFS
Cf. A267901.
Sequence in context: A243896 A202211 A104081 * A003455 A103275 A278209
KEYWORD
nonn
AUTHOR
R. H. Hardin, Jan 22 2016
STATUS
approved