What else

The function T is defined as:

T(x,y,z) = 
	if x ≤ y
		return y;
	else
		return T(T(x-1,y,z),T(y-1,z,x),T(z-1,x,y))

The function U is defined as:
U(n) = T(n,0,n+1)

We consider the number of times the else clause in the T function is invoked when computing U(n) (no memoization)
Let E(n) this number.

You are given E(5) = 223

What is E(100)?
Answer format: Give the digital sum of this huge number.

[My timing: < 100ms]