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 A049865 Number of iterations of unitary totient function (A047994) required to reach 1 from n. 7
 0, 1, 2, 3, 4, 2, 3, 4, 5, 4, 5, 3, 4, 3, 5, 6, 7, 5, 6, 4, 4, 5, 6, 4, 5, 4, 5, 6, 7, 5, 6, 7, 5, 7, 5, 5, 6, 6, 5, 7, 8, 4, 5, 6, 8, 6, 7, 6, 7, 5, 8, 6, 7, 5, 8, 5, 6, 7, 8, 5, 6, 6, 7, 8, 7, 5, 6, 7, 7, 5, 6, 6, 7, 6, 7, 6, 6, 5, 6, 6, 7, 8, 9, 6, 9, 5, 6, 6, 7, 8, 7, 6, 6, 7, 7, 7, 8, 7, 7, 7, 8, 8, 9, 7, 7, 7, 8, 6, 7, 8, 7 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS a(A003271(n)) = n and a(m) <> n for m < A003271(n). [Reinhard Zumkeller, Aug 17 2011] LINKS T. D. Noe, Table of n, a(n) for n = 1..10000 MAPLE A049865 := proc(n) if n = 1 then 0 ; else 1+procname( A047994(n)) ; end if; end proc: # R. J. Mathar, May 02 2013 MATHEMATICA uphi[n_] := (f = FactorInteger[n]; Times @@ (f[[All, 1]]^f[[All, 2]] - 1)); uphi[n_ /; n <= 1] = 1; a[n_] := (k = 0; FixedPoint[ (k++; uphi[#]) & , n]; k-1); Table[a[n], {n, 1, 120}] (* Jean-François Alcover, Jan 20 2012 *) PROG (Haskell) a049865 n = length \$ takeWhile (> 1) \$ iterate a047994 n a049865_list = map a049865 [1..] -- Reinhard Zumkeller, Aug 17 2011 CROSSREFS Sequence in context: A151925 A106653 A173524 * A070771 A274640 A245341 Adjacent sequences: A049862 A049863 A049864 * A049866 A049867 A049868 KEYWORD nonn,easy,nice AUTHOR David W. Wilson STATUS approved

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Last modified April 19 23:40 EDT 2024. Contains 371798 sequences. (Running on oeis4.)