A211078 1/4 the number of (2n)X(2n) 0..3 symmetric matrices with every element equal to two horizontal and vertical neighbors

1, 12, 408, 39072, 10448832, 7784500224, 16120594140672, 92699207728336896

Offset

1,2

Links

Table of n, a(n) for n=1..8.

Example

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

Crossrefs

Sequence in context: A285028 A292784 A003772 * A299382 A197038 A282883

Adjacent sequences: A211075 A211076 A211077 * A211079 A211080 A211081

Keyword

nonn

Author

R. H. Hardin Mar 31 2012

Status

approved