A199905 Number of -4..4 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2).

1, 6, 42, 152, 804, 5016, 24864, 139148, 814776, 4509164, 25781576, 149525280, 856571710, 4954153908, 28801991844, 167153096856, 973462118580, 5682734337828, 33191217303840, 194193233863080, 1137757795417530

Offset: 1

Author

R. H. Hardin Nov 11 2011

Keywords

• nonn

Comments

Column 4 of A199909.

Examples

			Some solutions for n=6
..0....3....1....4...-4....4....1....1....2...-2....3....4...-4...-3....2...-2
..2....1...-1...-3....1...-1....0....2...-2....3...-1...-1....4....2...-2....0
.-2...-4....3...-2...-3....3....2...-2....0...-4...-2...-2...-1....1....0....2
.-4....1....4...-1....1....1...-2....0....2...-3....2...-4....1....0....1....0
..1...-1...-3....3....2...-4...-4...-1....1....2...-3....4...-1....1...-1....4
..3....0...-4...-1....3...-3....3....0...-3....4....1...-1....1...-1....0...-4
		

Links

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

Crossrefs

Cf. A199909.