A211093 1/4 the number of n X n 0..3 symmetric matrices with every element equal to zero, two or three horizontal and vertical neighbors

1, 10, 247, 15457, 2424088, 951410443, 932290081063, 2278103185689373, 13868101018687422769, 210186367992374120026696

Offset

1,2

Links

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

Example

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

Crossrefs

Sequence in context: A034222 A197437 A268545 * A108792 A265854 A128013

Adjacent sequences: A211090 A211091 A211092 * A211094 A211095 A211096

Keyword

nonn

Author

R. H. Hardin Mar 31 2012

Status

approved