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A060197 Start at n, repeatedly apply pi(x) until reach 0; a(n) = number of steps to reach 0. 3
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, 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, 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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

The numbers at which this sequence jumps from n to n+1 are A007097(n).

LINKS

Table of n, a(n) for n=0..104.

FORMULA

Table[Length[FixedPointList[PrimePi, w]]-1, {w, 1, 1000}]

EXAMPLE

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.

CROSSREFS

Cf. A007097, A000720.

Sequence in context: A030602 A133947 A082090 * A116487 A249041 A070546

Adjacent sequences:  A060194 A060195 A060196 * A060198 A060199 A060200

KEYWORD

nonn

AUTHOR

Labos Elemer, Mar 19 2001

STATUS

approved

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Last modified December 15 11:43 EST 2019. Contains 329999 sequences. (Running on oeis4.)