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A333264
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Least number k that reaches 1 after n iterations of A206369.
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0
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1, 2, 3, 4, 5, 8, 15, 17, 69, 121, 137, 467, 985, 1949, 4049, 8117, 14641, 36383, 62501, 125003, 250007, 958081, 1817513, 3325981, 8062091, 21233813, 42467627, 125828819, 343955189
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OFFSET
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0,2
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COMMENTS
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Least number k such that A330786(k) = n.
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LINKS
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EXAMPLE
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a(5) = 8 since 8 is the least number that reaches 1 after 5 iterations of A206369: 8 -> 5 -> 4 -> 3 -> 2 -> 1.
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MATHEMATICA
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f[p_, e_] := Sum[(-1)^(e-k)*p^k, {k, 0, e}]; s[1] = 1; s[n_] := Times @@ (f @@@ FactorInteger[n]); numiter[n_] := Length @ FixedPointList[s, n] - 2; n = 0; seq={}; Do[If[numiter[k] == n, AppendTo[seq, k]; n++], {k, 1, 1000}]; seq
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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STATUS
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approved
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