f:N+→N+f : \mathbb{N}_+ \to \mathbb{N}_+f:N+→N+, f(x+y)=f(x)f(y)f(x+y) = f(x) f(y)f(x+y)=f(x)f(y), f(1)=2f(1) = 2f(1)=2. Find 2+∑n=12025f(n)2 + \sum_{n=1}^{2025} f(n)2+∑n=12025f(n).
220252^{2025}22025
220262^{2026}22026
320243^{2024}32024
None.
