Summed Fraction Factorials

Algebra Level 5

\[\frac {3}{1! + 2! + 3!} + \frac {4}{2! + 3! + 4!} + \frac {5}{3! + 4! + 5!} + \ldots + \frac {2001}{1999!+ 2000! + 2001!} = \frac {a}{b} - \frac {c}{d!}\]

The equation above holds true for coprime postive integers \(a\) and \(b\), and \(c\) and \(d\). What is the digit sum of \((abcd)^{(abc)^{(ab)^a}}\)?