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A226000
Number of pairs of orthogonal (-2,7) vectors of length 9*n.
1
2376, 473173920, 142896990300480, 20278050662801226240, 3273835406669841316064256, 637732143080315479532514447360, 115448330868966954716300528059883520
OFFSET
1,1
COMMENTS
Row 14 of A225987.
LINKS
EXAMPLE
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
CROSSREFS
Sequence in context: A250588 A165948 A183599 * A163026 A069300 A255800
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 22 2013
STATUS
approved