About Chebyshev - Pafnuty Lvovich Chebyshev (1821-1894)
Chebyshev - Pafnuty Lvovich Chebyshev (1821-1894)- Work on prime numbers included the determination of the number of primes not exceeding a given number, wrote an important book on the theory of congruences, proved that there was always at least one prime between n and 2n for n > 3.
