A199831 Number of -7..7 arrays x(0..n+1) of n+2 elements with zero sum and no two neighbors summing to zero.

140, 1820, 21364, 273728, 3579520, 47040968, 622300326, 8281149188, 110718596524, 1486040082748, 20010711643976, 270217094416868, 3657780168834780, 49618552941019396, 674346504318284036

Offset: 1

Author

R. H. Hardin Nov 11 2011

Keywords

• nonn

Comments

Column 7 of A199832

Examples

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

Links

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