A226000 Number of pairs of orthogonal (-2,7) vectors of length 9*n.

2376, 473173920, 142896990300480, 20278050662801226240, 3273835406669841316064256, 637732143080315479532514447360, 115448330868966954716300528059883520

Offset: 1

Author

R. H. Hardin, May 22 2013

Keywords

• nonn

Comments

Row 14 of A225987.

Examples

			Some solutions for n=1
.-2..7...-2..7...-2..7...-2..7...-2..7...-2..7....7..7...-2..7...-2..7....7..7
..7.-2....7.-2....7.-2....7..7....7..7....7..7...-2..7....7.-2...-2..7...-2..7
.-2..7...-2..7....7..7...-2..7...-2..7...-2..7....7.-2....7..7....7..7...-2..7
..7..7....7..7...-2..7...-2..7....7.-2....7.-2....7..7...-2..7...-2..7....7.-2
.-2..7....7.-2...-2..7...-2..7....7.-2....7..7...-2..7....7.-2....7.-2...-2..7
..7..7...-2..7....7..7...-2..7...-2..7....7.-2...-2..7....7..7...-2..7....7..7
..7.-2....7.-2...-2..7...-2..7....7.-2....7.-2....7.-2....7.-2...-2..7...-2..7
.-2..7....7..7....7.-2....7..7....7..7...-2..7...-2..7....7.-2...-2..7...-2..7
.-2..7...-2..7....7.-2...-2..7...-2..7...-2..7....7.-2....7.-2....7..7...-2..7
		

Links

• R. H. Hardin, Table of n, a(n) for n = 1..46