A210815 Number of (n+1)X(n+1) 0..3 symmetric matrices containing all values 0..3 with every 2X2 subblock having one or two distinct values, and new values 0..3 introduced in lower triangle row major order

0, 1, 168, 22071, 4205467, 1371990855, 822477585796, 938225630752531, 2077579958754422544, 9041912808668087622556, 77978293195183315063183805, 1340161768266449394440151104678

Offset

1,3

Links

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

Example

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

Crossrefs

Sequence in context: A075920 A181202 A076006 * A282375 A289327 A130215

Adjacent sequences: A210812 A210813 A210814 * A210816 A210817 A210818

Keyword

nonn

Author

R. H. Hardin Mar 27 2012

Status

approved