A199908 Number of -7..7 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2).

1, 10, 114, 680, 6064, 62776, 518560, 4854740, 47329800, 436295060, 4163000530, 40224691008, 383919683336, 3702037559404, 35864644194258, 346836775041832, 3366637367524806, 32752033994479420, 318790073410891420

Offset: 1

Author

R. H. Hardin Nov 11 2011

Keywords

• nonn

Comments

Column 7 of A199909

Examples

			Some solutions for n=6
.-2...-1....2...-7...-5...-2...-2...-2...-4...-5...-2...-4...-2...-3....4....0
.-1....7....7....1...-6....5...-1...-1....1...-3....5...-3....3...-7....3...-7
..4....0....5....2....5...-3....6...-6...-6....5....6....7....4....1...-1....4
.-1...-5...-5....6...-5....2...-7...-4....4...-5....2....5...-3....6...-5....2
..1....3...-7....1....6...-2....0....7....0....3...-5...-2....4...-4...-4...-5
.-1...-4...-2...-3....5....0....4....6....5....5...-6...-3...-6....7....3....6
		

Links

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