In 1850 P.L. Chebyshev and in 1932 P. Erdos proved that [n,2n] interval contains a prime. Bachraoui proved the case k = 2 in 2006. k=3 case proved by Andy Loo in 2011.
From the other hand Legendre’s Conjecture states that for any n, there is a prime in [n2, (n+1)2]. For instance between 132 (=169) and 142 (=196) there are five primes (173, 179, 181, 191, and 193).
This interests me and I formulated two different questions. I hope that the problems are interesting for someone else