A208304 Number of 4 X n nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any horizontal or antidiagonal neighbor (colorings ignoring permutations of colors).

1, 15, 877, 433252, 656404264, 2227156082842, 14216420563705724, 152834703739876070716, 2562708954761302163168116, 63338792205478132108785337770, 2209363673047740561377241754826088, 105080298194482216982100203776114994146, 6626004995903793205763315247117544349120572

Offset

0,2

Links

Andrew Howroyd, Table of n, a(n) for n = 0..100

Example

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

Crossrefs

Row 4 of A208301.

Sequence in context: A208349 A358802 A121292 * A258796 A232364 A264562

Adjacent sequences: A208301 A208302 A208303 * A208305 A208306 A208307

Keyword

nonn

Author

R. H. Hardin, Feb 25 2012

Extensions

a(0)=1 prepended and terms a(8) and beyond from Andrew Howroyd, May 18 2020

Status

approved