12

Part of 1998 Moldova Team Selection Test

Problems(1)

Compute $\sum_{n=0}^{3^k} \frac{1}{b_n}$

Source: Moldova TST 1998

k{}

be a positive integer. For every positive integer

n \leq 3^k

b_n

the greatest power of

3

C_{3^k}^n

\sum_{n=1}^{3^k-1} \frac{1}{b_n}