A202961 Number of arrays of n+2 integers in -7..7 with sum zero and adjacent elements differing in absolute value.

128, 1576, 17296, 207184, 2537024, 31155004, 384996502, 4786979780, 59791891464, 749603860520, 9427927830076, 118904758131236, 1503198371854568, 19043136745799960, 241690849746856584, 3072505406058890180

Offset: 1

Author

R. H. Hardin Dec 26 2011

Keywords

• nonn

Comments

Column 7 of A202962

Examples

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

Links

• R. H. Hardin, Table of n, a(n) for n = 1..210