A199698 Number of -2..2 arrays x(0..n-1) of n elements with zero sum and no two neighbors equal.

1, 4, 14, 52, 200, 708, 2642, 10000, 37984, 144876, 554120, 2128672, 8204180, 31697564, 122734614, 476170124, 1850664202, 7204005752, 28081918548, 109604285492, 428278469018, 1675246478864, 6559126501510, 25703606447364

Offset: 1

Author

R. H. Hardin Nov 09 2011

Keywords

• nonn

Comments

Column 2 of A199704

Examples

			Some solutions for n=5
..0....1...-2....0....2...-1....2....2....1....2...-1....2....1....0....2....0
.-1....0....2....1...-2....1....1....0...-1...-2....1...-1....2...-1...-1...-1
..1...-1...-1...-2....1...-1...-1...-1....0....0....0....1...-2....1....1....2
.-1...-2....0....0...-1....1...-2....1...-2...-1...-1....0...-1....2...-2...-1
..1....2....1....1....0....0....0...-2....2....1....1...-2....0...-2....0....0
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..200