A210931 Number of n X n 0..3 symmetric matrices with every element equal to zero, one or two horizontal and vertical neighbors, and new values 0..3 introduced in lower triangle row major order

1, 5, 178, 39460, 35878251, 125478724962, 1683060156006386, 86575081776631287402, 17078491833610134896199822, 12920202409647854108765238718313, 37484549282125499262636528834124614593

Offset

1,2

Links

Table of n, a(n) for n=1..11.

Example

Some solutions for n=4
..0..0..1..1....0..1..2..2....0..0..2..3....0..0..1..1....0..1..0..2
..0..0..0..1....1..0..2..1....0..1..2..2....0..1..0..0....1..1..0..2
..1..0..2..1....2..2..2..0....2..2..3..2....1..0..1..2....0..0..1..3
..1..1..1..1....2..1..0..3....3..2..2..0....1..0..2..1....2..2..3..3

Crossrefs

Sequence in context: A241115 A208196 A194571 * A141981 A136143 A035791

Adjacent sequences: A210928 A210929 A210930 * A210932 A210933 A210934

Keyword

nonn

Author

R. H. Hardin Mar 29 2012

Status

approved