The Erdős-Selfridge function g(k) is defined as the least integer bigger than k + 1 such that the least prime factor of (g(k) k) exceeds k, where (n k) is the binomial coefficient (Ecklund et al. 1974, Erdős et al. 1993). The best lower bound known is g(k)>=exp(csqrt((ln^3 k)/(ln ln k)))

binomial coefficient | good binomial coefficient | least prime factor

John Selfridge | Paul Erdős