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A197236
Number of n X n 0..4 arrays with each element x equal to the number of its horizontal and vertical neighbors equal to 4,3,2,1,2 for x=0,1,2,3,4.
1
1, 2, 15, 231, 10649, 1209990, 352842084, 271939715540, 541622294917014
OFFSET
1,2
COMMENTS
Every 0 is next to 0 4's, every 1 is next to 1 3's, every 2 is next to 2 2's, every 3 is next to 3 1's, every 4 is next to 4 2's.
EXAMPLE
Some solutions for n=4:
..0..2..2..0....0..1..3..1....0..0..0..0....0..0..0..0....2..2..2..2
..0..2..2..0....0..1..1..0....1..3..1..0....0..1..0..0....2..0..0..2
..0..0..1..0....1..3..0..0....0..1..0..0....1..3..2..2....2..0..2..2
..0..1..3..1....0..1..0..0....0..0..0..0....0..1..2..2....2..2..2..0
CROSSREFS
Diagonal of A197242.
Sequence in context: A090301 A297087 A247660 * A097628 A305111 A216860
KEYWORD
nonn,more
AUTHOR
R. H. Hardin, Oct 12 2011
STATUS
approved