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%I #14 Oct 30 2022 23:04:55
%S 2,3,4,4,5,5,5,5,5,5,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,7,7,7,7,
%T 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
%U 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7
%N Start at n, repeatedly apply pi(x) until reach 0; a(n) = number of steps to reach 0.
%C The numbers at which this sequence jumps from n to n+1 are A007097(n).
%F Table[Length[FixedPointList[PrimePi, w]]-1, {w, 1, 1000}]
%e For n=1000, the corresponding sequence of PrimePi-iteration is {1000,168,39,12,5,3,2,1,0}, whose length is a(1000)=9.
%Y Cf. A007097, A000720.
%K nonn
%O 1,1
%A _Labos Elemer_, Mar 19 2001
%E Offset corrected by _Sean A. Irvine_, Oct 30 2022
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