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 A327515 Number of steps to reach a fixed point starting with n and repeatedly taking the quotient by the maximum divisor that is 1, 2, or a nonprime number whose prime indices are pairwise coprime (A327512, A327514). 1
 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1, 0 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1 COMMENTS Positions of zeros are A289509. First term > 1 is a(225) = 2. First zero not in A318978 is a(17719) = 0. A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798. Numbers that are 1, 2, or a nonprime number whose prime indices are pairwise coprime are listed in A302696. LINKS FORMULA a(15^n) = n. EXAMPLE We have 50625 -> 3375 -> 225 ->  15 -> 1, so a(50625) = 4. MATHEMATICA primeMS[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]]; Table[Length[FixedPointList[#/Max[Select[Divisors[#], #==1||CoprimeQ@@primeMS[#]&]]&, n]]-2, {n, 100}] CROSSREFS See link for additional cross-references. Cf. A000005, A006530, A056239, A112798, A289509, A302569, A302696, A304711. Sequence in context: A188510 A131734 A134452 * A327532 A073445 A285589 Adjacent sequences:  A327512 A327513 A327514 * A327516 A327517 A327518 KEYWORD nonn AUTHOR Gus Wiseman, Sep 19 2019 STATUS approved

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Last modified September 23 15:42 EDT 2020. Contains 337310 sequences. (Running on oeis4.)