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 A085347 #16 Nov 19 2017 01:46:08
%S A085347 0,2,5,4,6,8,10,19,12,29,16,18,20,43,33,28,24,32,67,30,45,57,44,36,52,
%T A085347 101,63,85,91,48,64,86,137,66,149,99,106,163,60,129,88,80,105,72,197,
%U A085347 104,100,84,147,229,90,114,112,96,171,148,136,201,108,281,138,152,172
%N A085347 Least number x so that number of primes not exceeding sigma(x) equals n.
%H A085347 Vincenzo Librandi, <a href="/A085347/b085347.txt">Table of n, a(n) for n = 1..500</a>
%F A085347 a(n) = Min{x; A070803(x)=n};
%t A085347 {0}~Join~Table[x = 1; While[PrimePi@ DivisorSigma[1, x] != n, x++]; x, {n, 2, 63}] (* _Michael De Vlieger_, Feb 05 2017 *)
%o A085347 (PARI) a(n) = if (n==1, 0, x = 1; while(primepi(sigma(x))!= n, x++); x); \\ _Michel Marcus_, Dec 11 2013
%Y A085347 Cf. A000720, A000010, A000203, A070803, A070804, A085341-A085347.
%K A085347 nonn
%O A085347 1,2
%A A085347 _Labos Elemer_, Jul 10 2003