Primes with Restricted-Digit Differences

Rui Han, Yaghoub Rahimi, Fan Yang

Fix a base $b\ge 2$ and a digit set $\mathcal{D}\subset \{0,1,\dots ,b-1\}$, and let ${\mathcal{C}}_k$ be the set of integers in $[0,b^k)$ whose $k$ base-$b$ digits all lie in $\mathcal…