[math]b\left(n\right)=\frac{1}{n}\begin{matrix}n\\\sum\\k=1\end{matrix}\left(\lfloor2027\frac{n}{k}\rfloor-2027\lfloor\frac{n}{k}\rfloor\right)[/math][br][i]b[/i]([b]2027[/b]) = ?[br][right]Ötlet: [url=https://mail.google.com/mail/u/0/#inbox/FMfcgzQgLPVVcrPNbPfBbJDqkpnHphhV]Quora[/url][/right]