A222837 Number of nX7 0..3 arrays with no element equal to another at a city block distance of exactly two, and new values 0..3 introduced in row major order.

163, 6144, 5832, 10584, 22848, 55296, 138240, 301056, 642048, 1382400, 3022848, 6690816, 14816256, 32741376, 72244224, 159258624, 351111168, 774297600, 1707764736, 3766818816, 8308300800, 18324658176, 40416165888, 89140107264

Offset: 1

Author

R. H. Hardin Mar 06 2013

Keywords

• nonn

Comments

Column 7 of A222838

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..64

Formula

Empirical: a(n) = 2*a(n-1) +a(n-3) -2*a(n-4) +4*a(n-5) +a(n-6) -a(n-9) for n>14