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A074348 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. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
Michael De Vlieger, Table of n, a(n) for n = 1..42
Jason Earls, Smarandache iterations of the first kind on functions involving divisors and prime factors, in Smarandache Notions Journal (2004), Vol. 14.1, page 261.
MATHEMATICA
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 *)
CROSSREFS
Cf. A075661.
Sequence in context: A173080 A051062 A152531 * A063403 A355433 A348119
KEYWORD
nonn
AUTHOR
Jason Earls, Sep 23 2002
EXTENSIONS
a(28)-a(38) from Michael De Vlieger, Mar 28 2018
STATUS
approved

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Last modified March 28 10:31 EDT 2024. Contains 371240 sequences. (Running on oeis4.)