/ 10
| / 1\ |-1 + b|
| 1708984375*|1 - -| 5*|------|
| \ b/ | b |
| ----------------------- for ---------- < 1
| 11 6
| / 5*(-1 + b)\
| 2916*|1 - ----------|
| \ 6*b /
|
< oo
|_____
|\ `
| \ m
| \ m -m / 1\
| \ 5 *6 *|1 - -| *m!
| / \ b/ otherwise
| / ------------------
| / (-10 + m)!
|/____,
\m = 0
----------------------------------------------
10
21772800*(-1 + b)
$$\frac{\begin{cases} \frac{1708984375 \left(1 - \frac{1}{b}\right)^{10}}{2916 \left(1 - \frac{5 \left(b - 1\right)}{6 b}\right)^{11}} & \text{for}\: \frac{5 \left|{\frac{b - 1}{b}}\right|}{6} < 1 \\\sum_{m=0}^{\infty} \frac{5^{m} 6^{- m} \left(1 - \frac{1}{b}\right)^{m} m!}{\left(m - 10\right)!} & \text{otherwise} \end{cases}}{21772800 \left(b - 1\right)^{10}}$$
Piecewise((1708984375*(1 - 1/b)^10/(2916*(1 - 5*(-1 + b)/(6*b))^11), 5*Abs((-1 + b)/b)/6 < 1), (Sum(5^m*6^(-m)*(1 - 1/b)^m*factorial(m)/factorial(-10 + m), (m, 0, oo)), True))/(21772800*(-1 + b)^10)