Well it's me, Marko Riedel. ;-)
Egorychev method for combinatorial number sums PDF and Riemann Zeta Function FEQ PDF and Coupon collector and EGFs PDF and Exponential formula PDF.
Recommended reading:
III. Power Group Enumeration of $k$-subsets of a standard deck of 52 cards under suit permutation
XVI. Barnes integral, Stirling numbers and coefficient asymptotics
XXVI. Annihilating coefficient extractors and Stirling numbers
XXXI. Counting labelled / unlabelled endofunctions up to isomorphism
Recent work generally better than early work. Best-of.