Number of pairs of orthogonal (-1,2) vectors of length 3*n.
A225988
Number of pairs of orthogonal (-1,2) vectors of length 3*n.
Terms
- a(0) =9a(1) =390a(2) =20160a(3) =1106424a(4) =62606544a(5) =3611217792a(6) =211096262400
External references
- oeis: A225988