Check my calculation for heritability in an asexual population

Did I get this calculation correct? (FYI, this is an example of my own.) Gen #1=Suppose an individual, A, produces 3 offspring called B, C, and D. Gen #2=Suppose B produces 2 offspring called E and F. Suppose C produces 1 offspring called G. Suppose D produces 0 offspring. Gen #3=Suppose E produces 2 offspring called H and I. Suppose F produces 0 offspring. Suppose G produces 1 offspring called J. At this juncture, there are six pairs: A, B=(3, 2), A, C=(3, 1), A, D=(3, 0), B, E=(2, 2), B, F=(2, 0), C, G=(1, 1)… Mean of parents: 3+3+3+2+2+1=14 /6 =2.333 Mean of offspring: 2+1+0+2+0+1=6 /6 =1 Calculation of covariance: [(3-2.333)*(2-1)+(3-2.333)*(1-1)+(3-2.333)*(0-1)+(2-2.333)*(2-1)+(2-2.333)*(0-1)+(1-2.333)*(1-1)] = 0 /6 =0 Calculation of variance of parental values: [(3-2.333)^2+(3-2.333)^2+(3-2.333)^2+(2-2.333)^2+(2-2.333)^2+(1-2.333)^2] = 3.333 /6 =.55555 Heritability: 0 /.55555 = 0