A198910 Number of nX4 0..7 arrays with values 0..7 introduced in row major order and no element equal to any horizontal or vertical neighbor.

5, 500, 269940, 319608038, 481871809749, 769126451071174, 1243368053336112649, 2015791720035206825303, 3270193421121063659774745, 5305976942994216714747844079, 8609380449975858170849466245738

Offset: 1

Author

R. H. Hardin Oct 31 2011

Keywords

• nonn

Comments

Column 4 of A198914

Examples

			Some solutions with values 0 to 7 for n=3
..0..1..2..3....0..1..0..2....0..1..2..3....0..1..2..1....0..1..0..2
..3..4..5..2....3..4..5..3....4..5..0..6....3..4..5..6....2..0..3..4
..6..7..1..6....6..1..7..2....2..7..6..5....4..7..0..7....3..5..6..7
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..123

Formula

Empirical: a(n) = 2296*a(n-1) -1239092*a(n-2) [phone]*a(n-3) -24632440060*a(n-4) [phone]*a(n-5) -44994493075469*a(n-6) [phone]*a(n-7) -13429762946315149*a(n-8) +124540876930445980*a(n-9) -765040702294085198*a(n-10) +3074302608489782520*a(n-11) -7884335188124038674*a(n-12) +12438514719451024794*a(n-13) -11471383995777540513*a(n-14) +5595786642970619820*a(n-15) -1099871574411268404*a(n-16)