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
Keywords
Examples
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
Links
- Andrew Howroyd, Table of n, a(n) for n = 1..140
Crossrefs
Column 4 of A207868.
Extensions
Terms a(11) and beyond from Andrew Howroyd, Mar 11 2023