CollapseProblem 695Let p1<p2<⋯p_1<p_2<\cdotsp1<p2<⋯ be a sequence of primes such that pi+1≡1(modpi)p_{i+1}\equiv 1\pmod{p_i}pi+1≡1(modpi). Is it true that limkpk1/k=∞?\lim_k p_k^{1/k}=\infty?klimpk1/k=∞? Does there exist such a sequence with pk≤exp(k(logk)1+o(1))?p_k \leq \exp(k(\log k)^{1+o(1)})?pk≤exp(k(logk)1+o(1))?Source: erdosproblems.com/695Number theoryWiki pageStatusOpenNo claim settles this problem.ReferencesFKL10Ford, Kevin and Konyagin, Sergei V. and Luca, Florian, Prime chains and Pratt trees. Geom. Funct. Anal. (2010), 1231-1258.