Since
For calculating number of total min/max heaps of some n elements
T(n) =(n-1)Ck*T(k)*T(n-k)
Where n is number of elements given and k is number of child in right subtree
By bottom up approach we can see the structure of heap with 8 elements
1
2 3
4 5 6 7
8
We can see that right subtree will have 3 nodes
So
k= 3 and n= 8
Putting these values in above formula
T(8)=7C3*T(3)*T(4)
By same method we calcute T(3) and T(4)
we get
T(8) = 35*2*3= 210