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Length of FixedPointList approximating (2^n)-th composite number. See program link below.
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%I #8 Oct 15 2013 22:31:26

%S 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 8,8,8,9,9,9,9,9,10,10,9,10

%N Length of FixedPointList approximating (2^n)-th composite number. See program link below.

%C Number of iterations needed to reach the composite number using the formula in the program.

%e n=30: {1073741824, 1128141853, 1130754984, 1130880243, 1130886219, 1130886489, 1130886503, 1130886504}, so a(30)=8.

%t Table[ Length[ FixedPointList[ 2^n+PrimePi[ # ]+1 &, 2^n]]-1, {n, 0, 45}]

%Y Cf. A002808, A073255-A073264, A065856.

%K nonn

%O 0,1

%A _Labos Elemer_, Jul 22 2002

%E Extended by _Robert G. Wilson v_, Jul 24 2002