Question 111
Let $s(n)$ denote the number of 1's in the binary representation of $n$. Compute
$$
\frac{1}{255} \sum_{0 \leq n \lt 16} 2^{n}(-1)^{s(n)}
$$
$$
\frac{1}{255} \sum_{0 \leq n \lt 16} 2^{n}(-1)^{s(n)}
$$
MathNet 2009-part-05 — 172 problems (EN–VI) Question 111
Math Olympiad Vault · MathNet 2009-part-05 — 172 problems (EN–VI)