A210932 Number of n X n 0..3 symmetric matrices with every element equal to zero, one, three or four horizontal and vertical neighbors, and new values 0..3 introduced in lower triangle row major order.

1, 2, 55, 6136, 2300729, 2853666014, 11691775609193, 158256127017674737, 7077134333752159967353, 1045606338210715698434693227

Offset

1,2

Links

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

Example

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

Crossrefs

Sequence in context: A024029 A134501 A210928 * A278842 A307025 A376667

Adjacent sequences: A210929 A210930 A210931 * A210933 A210934 A210935

Keyword

nonn

Author

R. H. Hardin, Mar 29 2012

Extensions

Name corrected by Andrew Howroyd, Mar 25 2025

Status

approved