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A074348
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Smallest number requiring n steps to reach 0 or -1 when iterating the function: f(n)=lcd(n)-lpf(n), where lcd(n) is the largest common difference between consecutive divisors of n (ordered by size) and lpf(n) is the largest prime factor of n.
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2
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1, 8, 24, 45, 75, 160, 273, 429, 741, 1001, 1183, 1547, 2645, 3553, 4301, 5423, 10880, 23465, 33371, 39109, 49075, 74011, 98933, 104371, 107911, 163489, 263177, 371591, 409219, 420727, 631215, 986537, 1234459, 1440299, 2777775, 3101857, 3412783, 3626797
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OFFSET
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1,2
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LINKS
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MATHEMATICA
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With[{s = Array[Length@ NestWhileList[Function[n, Max@ Differences@ # - SelectFirst[Reverse@ #, PrimeQ] &@ Divisors[n]], #, # > 0 &] &, 10^5]}, Array[FirstPosition[s, #][[1]] &, Max@ s - 1, 2]] (* Michael De Vlieger, Mar 28 2018 *)
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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