A203968 Number of n X n 0..2 arrays with every 1 immediately preceded by 0 to the left or above, and every 2 immediately preceded by 0 1 to the left or above

1, 7, 258, 34799, 22100882, 64449537503, 847220834970347, 50681890300309193984, 13775254400039658772386790, 17006093281906665293267116254138

Offset

1,2

Comments

Diagonal of A203975

Links

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

Example

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

Crossrefs

Sequence in context: A165437 A232304 A254127 * A174251 A269576 A130741

Adjacent sequences: A203965 A203966 A203967 * A203969 A203970 A203971

Keyword

nonn

Author

R. H. Hardin Jan 08 2012

Status

approved