Question 179
Determine all natural numbers $n \geq 2$ such that for all integers $0 \leq i, j \leq n$:
$$
i+j \equiv \binom{n}{i}+\binom{n}{j} \quad(\bmod 2)
$$
$$
i+j \equiv \binom{n}{i}+\binom{n}{j} \quad(\bmod 2)
$$
MathNet 2018-part-05 — 181 problems (EN–VI) Question 179
Math Olympiad Vault · MathNet 2018-part-05 — 181 problems (EN–VI)