This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A110077 #25 Mar 04 2018 03:12:02
%S A110077 1,0,0,0,8743,71193,640737,5906061,65624979,590624811,5498542791,
%T A110077 55995364341,549871699041,5582882097891,55828827410391,
%U A110077 542546715730761,5469955867029591,53226216007355979,532262221390168479,5300249369031696429,52602977416561263909,531074469279114815229
%N A110077 a(n) is the smallest number m such that sigma(m)=10^n and if there is no such m, a(n)=0.
%C A110077 A110078(n) gives number of solutions of the equation sigma(x)=10^n.
%C A110077 Conjecture: For n>3 a(n) is positive.
%H A110077 Max Alekseyev, <a href="/A110077/b110077.txt">Table of n, a(n) for n = 0..1000</a>
%H A110077 Max Alekseyev, <a href="http://home.gwu.edu/~maxal/gpscripts/">PARI/GP scripts for miscellaneous math problems</a>
%H A110077 Max A. Alekseyev, <a href="https://www.emis.de/journals/JIS/VOL19/Alekseyev/alek5.html">Computing the Inverses, their Power Sums, and Extrema for Euler's Totient and Other Multiplicative Functions</a>. Journal of Integer Sequences, Vol. 19 (2016), Article 16.5.2
%e A110077 a(9)=590624811 because sigma(590624811)=sigma(3^3*7*3124999) sigma(3^3)*sigma(7)*sigma(3124999)=40*8*3125000=10^9 and 590624811 is the smallest number m with this property (sigma(m)=10^9).
%o A110077 (PARI) { a(n) = invsigma(10^n)[1] } \\ _Max Alekseyev_, Apr 26 2010
%Y A110077 Cf. A110076, A110078.
%K A110077 nonn
%O A110077 0,5
%A A110077 _Farideh Firoozbakht_, Aug 01 2005
%E A110077 a(10)-a(11) from _Donovan Johnson_ and _Farideh Firoozbakht_, Nov 22 2008
%E A110077 a(12) onward from _Max Alekseyev_, Apr 26 2010, Mar 06 2014