Today I entered the following expression in maple:
$$a_i = H_{10^i} - ln(10^i) - \gamma$$
Here $H_j$ equals $\sum_{k=1}^{j} 1/k$ and $\gamma$ is the Euler-Mascheroni constant. 

When I computed $a_n$ for $i = 0$ to $10$ I obtained the following results:

\begin{itemize}

\item $i = 0$; 
4.227843350984671393934879099175975689578406640600764011942327651151323 * 10^{-1}

\item $i=1$;
4.9167496072675423629464709201487329610707429399557393414873118115813 * 10^{-2}

\item $i=2$; 
4.991666749996032162622676207122311664609813510982102304110919767206 * 10^{-3}

\item $i=3$ 4.999166666749999960317501984051226762153678825611388678758121701133 * 10^{-4}

\item $i=4$; 4.99991666666674999999960317460734126976551226762154503821179264423 * 10^{-5}

\item $i=5$; 4.9999916666666667499999999960317460321626984126226551226762154523 * 10^{-6}

\item $i=6$; 4.999999166666666666749999999999960317460317501984126984051226523 * 10^{-7}

\item $i=7$; 4.99999991666666666666674999999999999960317460317460734126984123 * 10^{-8}

\item $i=8$;                                                                        
4.9999999916666666666666667499999999999999960317460317460321623 \cdot 10^{-9}

\item $i=9$;                                                                          
4.999999999166666666666666666749999999999999999960317460317423 * 10^{-10}   

\item $i=10$;
4.99999999991666666666666666666674999999999999999999960317423* 10^{-11}
\end{itemize}

So we see that the periodic strips of ...99999..., of ...66666... and ...99999... an many other periods increase for even larger $i$. The question is now: Is there any rule behind it that the remainder term $a_i$ behaves that way?