There are $n$ distinct piles of stones, each of size $n-1$. Starting with an initial score of $0$, the following procedure is repeated:
If all piles are eventually emptied, the current score is confirmed as final. However, if one gets "stuck" and cannot empty all piles, the current score is discarded, resulting in a final score of $0$.
Three example sequences of turns are illustrated below for $n=4$, with each tuple representing pile sizes as one proceeds, and with additions to the score indicated above the arrows. $$ \begin{align} &(3,3,3,3)\xrightarrow{+1}(0,3,2,3)\xrightarrow{+1}(0,3,1,0)\xrightarrow{+1}(0,0,0,0)&:\quad\text{final score }=3\\ &(3,3,3,3)\xrightarrow{+1}(3,0,3,2)\xrightarrow{+2}(1,0,3,0)\xrightarrow{+1}(0,0,0,0)&:\quad\text{final score }=4\\ &(3,3,3,3)\xrightarrow{+2}(1,3,1,3)\xrightarrow{+1}(1,2,1,0)\rightarrow\text{stuck!}&:\quad\text{final score }=0 \end{align} $$
Define $F(n)$ to be the sum of the final scores achieved for every sequence of turns which successfully empty all piles.
You are given $F(3)=12$, $F(4)=360$, and $F(8)=16785941760$.
Find $F(100)$. Give your answer modulo $10^9+7$.