A199699 Number of -3..3 arrays x(0..n-1) of n elements with zero sum and no two neighbors equal.

1, 6, 32, 168, 892, 4964, 27854, 156920, 891684, 5095360, 29236016, 168361392, 972601784, 5633548460, 32706291872, 190266981972, 1108856802378, 6472638961608, 37836350087956, 221461180199752, 1297757839607606

Offset: 1

Author

R. H. Hardin Nov 09 2011

Keywords

• nonn

Comments

Column 3 of A199704

Examples

			Some solutions for n=5
..1....0....2...-3....1...-3...-2...-3...-2....0....1....2....2....2...-2....0
.-1....1....0....1....2....2....1....3...-1....2....2....0....0...-2...-3....3
.-3...-1....1...-2...-2....1...-2....0....0....1...-3...-1...-3....3....3....2
..3...-2...-3....1....0...-2....2....1....3...-2....1....1...-1...-1....2...-3
..0....2....0....3...-1....2....1...-1....0...-1...-1...-2....2...-2....0...-2
		

Links

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