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 A073261 #8 Oct 15 2013 22:31:26
%S A073261 4,4,3,3,3,4,3,5,4,4,5,4,5,6,6,6,6,5,6,6,7,6,6,6,7,7,8,7,7,8,8,8,8,8,
%T A073261 8,8,8,9,9,9,9,9,10,10,9,10
%N A073261 Length of FixedPointList approximating (2^n)-th composite number. See program link below.
%C A073261 Number of iterations needed to reach the composite number using the formula in the program.
%e A073261 n=30: {1073741824, 1128141853, 1130754984, 1130880243, 1130886219, 1130886489, 1130886503, 1130886504}, so a(30)=8.
%t A073261 Table[ Length[ FixedPointList[ 2^n+PrimePi[ # ]+1 &, 2^n]]-1, {n, 0, 45}]
%Y A073261 Cf. A002808, A073255-A073264, A065856.
%K A073261 nonn
%O A073261 0,1
%A A073261 _Labos Elemer_, Jul 22 2002
%E A073261 Extended by _Robert G. Wilson v_, Jul 24 2002