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A073261
Length of FixedPointList approximating (2^n)-th composite number. See program link below.
0
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, 8, 8, 8, 9, 9, 9, 9, 9, 10, 10, 9, 10
OFFSET
0,1
COMMENTS
Number of iterations needed to reach the composite number using the formula in the program.
EXAMPLE
n=30: {1073741824, 1128141853, 1130754984, 1130880243, 1130886219, 1130886489, 1130886503, 1130886504}, so a(30)=8.
MATHEMATICA
Table[ Length[ FixedPointList[ 2^n+PrimePi[ # ]+1 &, 2^n]]-1, {n, 0, 45}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Jul 22 2002
EXTENSIONS
Extended by Robert G. Wilson v, Jul 24 2002
STATUS
approved