I have no good references but:

The mini character was supposed to be the shipwright and was replaced by Franky.

The other one was meant to be a plant obsessed character who was replaced by Robin and largely incorporated into the post time skip Ussop.

Who are the members of an early design of Luffy's crew?
Numerical experiments suggest that
$\binom{2m}{m + k}\cdot\frac{3m - 1 - 2k^2}{2m - 1}$
is integer for all $-m \le k\le +m$. It means that expression evaluation could be implemented very efficiently, only using integer addition and multiplication.

However, I'm failed to derive computationally efficient expression so far.
The two ideas I have are linear combination of binomials, and recursion -- but more insight is needed to go further.
