A207866 Number of n X 4 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or vertical neighbor (colorings ignoring permutations of colors).

5, 500, 278982, 455546040, 1625686993918, 10764437129618296, 119010390034543491042, 2040368351234509987725212, 51350903376256822436382238230, 1818472780230512625778385363238944, 87604972777997602798029710458933219862, 5585379463993456459896660751935863285859008

Offset

1,1

Links

Andrew Howroyd, Table of n, a(n) for n = 1..140

Example

Some solutions for n=5
..0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1....0..1..0..1
..1..0..1..0....1..0..1..0....1..2..3..2....1..0..1..0....1..2..1..0
..0..1..0..1....0..1..2..1....0..1..0..1....0..1..2..1....0..1..0..1
..1..2..1..0....1..0..1..0....1..0..1..0....1..0..1..0....1..2..1..0
..0..1..0..1....0..1..3..1....0..1..0..1....0..1..0..1....0..1..2..1

Crossrefs

Column 4 of A207868.

Sequence in context: A124358 A198719 A198910 * A013305 A114066 A014287

Adjacent sequences: A207863 A207864 A207865 * A207867 A207868 A207869

Keyword

nonn

Author

R. H. Hardin, Feb 21 2012

Extensions

Terms a(11) and beyond from Andrew Howroyd, Mar 11 2023

Status

approved