A211083 1/4 the number of n X n 0..3 symmetric matrices with every element equal to two or three horizontal and vertical neighbors

0, 1, 0, 12, 18, 624, 6012, 228984, 8210664, 619049280, 63783422784, 11382530540616

Offset

1,4

Links

Table of n, a(n) for n=1..12.

Example

Some solutions for n=6
..1..1..1..1..1..1....2..2..1..1..0..0....2..2..0..0..1..1....0..0..3..3..1..1
..1..3..3..1..1..1....2..2..1..1..0..0....2..2..0..0..1..1....0..0..3..3..1..1
..1..3..3..1..2..2....1..1..2..2..3..3....0..0..1..1..2..2....3..3..2..2..1..1
..1..1..1..1..2..2....1..1..2..2..3..3....0..0..1..1..2..2....3..3..2..2..1..1
..1..1..2..2..0..0....0..0..3..3..2..2....1..1..2..2..0..0....1..1..1..1..2..2
..1..1..2..2..0..0....0..0..3..3..2..2....1..1..2..2..0..0....1..1..1..1..2..2

Crossrefs

Sequence in context: A212128 A110932 A112880 * A100541 A337424 A056688

Adjacent sequences: A211080 A211081 A211082 * A211084 A211085 A211086

Keyword

nonn

Author

R. H. Hardin Mar 31 2012

Status

approved