T(n,k)=Number of pairs of orthogonal (-x,y) vectors of length k*(x+y), where x/y is the n-th rational <= 1, ordered first by y and then x, e.g. 1/1, 1/2, 1/3, 2/3, 1/4, 3/4 ...
A225987
T(n,k)=Number of pairs of orthogonal (-x,y) vectors of length k*(x+y), where x/y is the n-th rational <= 1, ordered first by y and then x, e.g. 1/1, 1/2, 1/3, 2/3, 1/4, 3/4 ...
Terms
- a(0) =4a(1) =48a(2) =9a(3) =640a(4) =390a(5) =20a(6) =8960a(7) =20160a(8) =3192a(9) =60a(10) =129024a(11) =1106424a(12) =652784a(13) =48720a(14) =45a(15) =1892352a(16) =62606544a(17) =134432480a(18) =41801760a(19) =26010a(20) =420a(21) =28114944a(22) =3611217792a(23) =28244153600a(24) =36951200000a(25) =21594300a(26) =8168160a(27) =102a(28) =421724160a(29) =211096262400
External references
- oeis: A225987