



 
We have two responses for you You are right. For any positive integer n, there is always a prime between n and 2n. This is known as Bertrand's Postulate. Victoria
It is certainly true, but not trivial to prove, that there is a prime between n and 2n for n > 1  this statement was first conjectured in 1845 by Joseph Bertrand (1822–1900). Bertrand himself verified his statement for all numbers up to 3 million. His conjecture was proved by Chebyshev (1821–1894) in 1850 and so the postulate is often known as Chebyshev's theorem. There are much stronger results for n large enough but of course, the proofs get more and more difficult. Penny  


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