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
Keywords
Examples
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
Links
- Andrew Howroyd, Table of n, a(n) for n = 0..100
Crossrefs
Row 4 of A208301.
Extensions
a(0)=1 prepended and terms a(8) and beyond from Andrew Howroyd, May 18 2020