A210922 Number of n X n 0..3 symmetric matrices with every element equal to one or two horizontal and vertical neighbors, and new values 0..3 introduced in lower triangle row major order

0, 1, 2, 49, 3312, 818235, 488196032, 845278581938, 3889846475035188, 49699973559580684560

Offset

1,3

Links

Table of n, a(n) for n=1..10.

Example

Some solutions for n=4
..0..0..1..1....0..0..1..0....0..0..1..1....0..0..2..2....0..0..1..0
..0..0..2..0....0..1..1..0....0..0..1..1....0..1..1..1....0..0..1..0
..1..2..2..0....1..1..2..2....1..1..2..2....2..1..0..0....1..1..1..0
..1..0..0..0....0..0..2..2....1..1..2..2....2..1..0..0....0..0..0..0

Crossrefs

Sequence in context: A221134 A243720 A369943 * A257742 A269839 A088067

Adjacent sequences: A210919 A210920 A210921 * A210923 A210924 A210925

Keyword

nonn

Author

R. H. Hardin Mar 29 2012

Status

approved