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 A036452 #19 Jan 03 2015 04:40:31
%S A036452 1,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
%T A036452 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,3,2,2,2,2,2,2,2,2,
%U A036452 2,2,2,3,2,2,2,2,2,2,2,2,2,2,2,3,2,2,2,2,2,3,2,2,2,2,2,3,2,2,2,2,2,2,2,2,2
%N A036452 a(n) = d(d(d(d(n)))), the 4th iterate of number-of-divisors function with initial value of n.
%C A036452 The iterated d function rapidly converges to fixed point 2. For k=4, the first n for which a(n)>2 is 60.
%H A036452 Enrique Pérez Herrero, <a href="/A036452/b036452.txt">Table of n, a(n) for n = 1..2000</a>
%F A036452 a(n) = d(d(d(d(n)))).
%e A036452 E.g., n=96 and its successive iterates are 12,6,4,3 and 2. The 4th term is a(96)=3.
%t A036452 f[n_]:=DivisorSigma[0,n]; Table[Nest[f,n,4], {n,100}] (* _Vladimir Joseph Stephan Orlovsky_, Mar 10 2010 *)
%o A036452 (PARI) a(n)=my(d=numdiv);d(d(d(d(n)))) \\ _Charles R Greathouse IV_, Apr 07 2012
%Y A036452 Cf. A000005, A010553, A036450, A036453.
%K A036452 nonn
%O A036452 1,2
%A A036452 _Labos Elemer_