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 A199858 #19 Mar 30 2012 18:36:00
%S A199858 1,2,3,9,7,1,9,5,3,8,1,4,6,2,2,7,4,1,1,9,6,5,0,4,2,6,7,6,5,2,4,5,8,7,
%T A199858 1,0,4,6,7,9,0,0,0,3,6,4,6,2,3,5,4,2,7,4,1,4,2,9,5,8,6,3,0,5,7,6,9,8,
%U A199858 9,8,3,3,8,1,7,1,7,6,5,2,1,5,0,9,6,0,2,6,2,4,8,4,8,9,7,7,1,1,4,7,6,8,7,0,3
%N A199858 Decimal expansion of Sum_{n = 1 .. infinity }[ 1 / Sum {i = 1 .. m} d(i)^n] where d(i) are the divisors of n and m = tau(n) is the number of divisors of n.
%e A199858 1.23971953814622741196504267652458710467...
%t A199858 RealDigits[N[Sum[1/DivisorSigma[n,n],{n,1,100}],130]][[1]]
%K A199858 nonn,cons
%O A199858 1,2
%A A199858 _Michel Lagneau_, Nov 28 2011