On powers associated with Sierpiński numbers, Riesel numbers and Polignac's conjecture

We address conjectures of P. Erdős and conjectures of Y.-G. Chen concerning the numbers in the title. We obtain a variety of related results, including a new smallest positive integer that is simultaneously a Sierpiński number and a Riesel number and a proof that for every positive integer r, there is an integer k such that the numbers k,k2,k3,…,kr are simultaneously Sierpiński numbers.