|
|
A225988
|
|
Number of pairs of orthogonal (-1,2) vectors of length 3*n.
|
|
1
|
|
|
9, 390, 20160, 1106424, 62606544, 3611217792, 211096262400, 12461757863808, 741242882016000, 44355068641175040, 2667095701669969920, 161021441731743129600, 9754428938330096713728, 592621128107578217201664
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
|
|
LINKS
|
|
|
EXAMPLE
|
All solutions for n=1
.-1.-1...-1..2...-1..2...-1..2....2..2...-1..2...-1.-1....2..2...-1..2
.-1..2...-1.-1....2.-1....2..2...-1..2....2..2...-1.-1...-1..2...-1..2
.-1.-1...-1.-1....2..2....2.-1....2.-1...-1..2...-1..2...-1..2....2..2
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|