A208000 Number of nX4 nonnegative integer arrays with new values 0 upwards introduced in row major order and no element equal to any knight-move neighbor (colorings ignoring permutations of colors).

15, 1657, 426422, 450288795, 1182700979380, 6184248124218800, 56513375910372605548, 826725568737937330039810, 18171823971396715681105965282, 572057633247843506849301892746850, 24840621984533068280588275487942834483, 1443495070617319156132945205013820325621405

Offset: 1

Author

R. H. Hardin, Feb 22 2012

Keywords

• nonn

Examples

			Some solutions for n=4
..0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0....0..0..0..0
..1..1..1..1....1..1..1..1....1..1..1..1....1..1..1..2....1..1..1..1
..2..2..2..3....2..2..2..2....2..2..2..2....2..1..2..2....2..2..2..2
..0..0..0..0....0..0..0..0....3..3..0..0....0..0..3..4....0..0..3..0
		

Links

• Andrew Howroyd, Table of n, a(n) for n = 1..50

Crossrefs

Column 4 of A208001.

Extensions

Terms a(6) and beyond from Andrew Howroyd, Jul 01 2017