From this OEIS Sequence:
$a(n+1) = (d+0^d)*10^{\lfloor{(log_{10}{a(n)+1))}}\rfloor} + (1-0^d)*\lfloor(a(n)/10)\rfloor$, where $d \equiv (a(n)+1) \,(mod \, 10)$
I want to know what that "$0^d$" means? Because when $d = 0$ we have a problem, and in rest of cases $0^d = 0$. Sorry if it is a stupid question but I don't understand. Thanks!