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A301945
Number of n X n 0..1 arrays with every element equal to 1, 2 or 3 horizontally or antidiagonally adjacent elements, with upper left element zero.
1
0, 2, 20, 947, 120815, 58609226, 86143630040, 418568449327270, 6527100767589040926, 331808147283786972146018, 54543586667142977292165721500, 29084806316831133817614992597097070
OFFSET
1,2
COMMENTS
Diagonal of A301951.
LINKS
EXAMPLE
Some solutions for n=5
..0..0..0..0..0. .0..0..0..1..1. .0..0..1..1..0. .0..0..0..1..1
..0..1..0..1..1. .0..1..0..0..0. .0..1..1..0..0. .0..1..0..0..0
..1..1..1..0..0. .1..0..1..1..0. .1..0..1..0..0. .1..1..1..0..0
..1..0..0..0..1. .0..0..1..0..1. .0..1..1..1..1. .1..0..0..1..0
..1..1..1..1..1. .0..1..0..1..1. .1..0..0..0..0. .0..1..1..0..0
CROSSREFS
Cf. A301951.
Sequence in context: A006547 A290883 A135757 * A158843 A008793 A361297
KEYWORD
nonn
AUTHOR
R. H. Hardin, Mar 29 2018
STATUS
approved