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A225989
Number of pairs of orthogonal (-1,3) vectors of length 4*n.
1
20, 3192, 652784, 134432480, 28244153600, 6052498776192, 1314942362273280, 288501497813552640, 63776322167821168640, 14182989297327325110272, 3169467786802943379238912, 711136363409644515952173056
OFFSET
1,1
COMMENTS
Row 3 of A225987.
LINKS
EXAMPLE
Some solutions for n=1
.-1..3...-1..3....3..3...-1..3...-1..3...-1..3...-1..3...-1.-1....3..3...-1..3
..3..3...-1..3...-1..3....3..3...-1..3....3.-1...-1..3...-1.-1...-1..3....3.-1
.-1..3....3..3...-1..3....3.-1....3.-1....3..3...-1..3...-1.-1....3.-1....3..3
..3.-1....3.-1....3.-1...-1..3....3..3...-1..3....3..3...-1..3....3.-1....3.-1
CROSSREFS
Sequence in context: A250019 A145405 A028458 * A332265 A177323 A184891
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 22 2013
STATUS
approved