180 citations · 357 across the 58 of their papers we have counts for
Showing 2009Show all
3 papers · 1 filter
math.NT2009
Chebyshev's bias for products of two primes
Kevin Ford, Jason Sneed
Under two assumptions, we determine the distribution of the difference between two functions each counting the numbers < x that are in a given arithmetic progression modulo q and t…
math.NT2009★ 14 cited
Common values of the arithmetic functions phi and sigma
Kevin Ford, Florian Luca, Carl Pomerance
We show that the equation phi(a)=σ(b) has infinitely many solutions, where phi is Euler's totient function and sigma is the sum-of-divisors function. This proves a 50-year old conj…
math.NT2009★ 1 cited
Prime chains and Pratt trees
Kevin Ford, Sergei V. Konyagin, Florian Luca
We study the distribution of prime chains, which are sequences p_1,...,p_k of primes for which p_{j+1}\equiv 1\pmod{p_j} for each j. We give estimates for the number of chains with…