Erdős problem 249Is ∑nϕ(n)2n\sum_{n} \frac{\phi(n)}{2^n} irrational? Here ϕ\phi is the Euler totient function.WorkspaceContinue locallyOpen sourceSign in to contributeOpen this exact Problem, source revision, and authority Repository in Workbench. This handoff does not clone, switch, upload, or execute anything.FilesErdős problem 2492 retained source recordsCanvaspublic previewSource#249→ResultNone→Checks0