M + l <-> ml
k1 = [ml]/[m]*[l]

ml + l <-> ml2
k2 = [ml2]/[ml]*[l]

ml2 + l <-> ml3
k3 = [ml3]/[ml2]*[l]

ml3 + l <-> ml4
k4 = [ml4]/[ml3]*[l]

***

m + l <-> ml
b1 = [ml]/[m]*[l] = k1

m + 2 l <-> ml2
b2 = [ml2]/[ml*[l]^2 = k1*k2

m + 3l <-> ml3
b3 = [ml3]/[m]*[l]^3 = k1*k2*k3


m + 4l <-> ml4
b4 = [ml4]/[m]*[l]^4 = k1*k2*k3*k4