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A117818 a(n) = n if n is 1 or a prime, otherwise a(n) = n divided by the least prime factor of n (A032742(n)). 3

%I

%S 1,2,3,2,5,3,7,4,3,5,11,6,13,7,5,8,17,9,19,10,7,11,23,12,5,13,9,14,29,

%T 15,31,16,11,17,7,18,37,19,13,20,41,21,43,22,15,23,47,24,7,25,17,26,

%U 53,27,11,28,19,29,59,30,61,31,21,32,13,33,67,34,23,35,71,36,73,37,25,38

%N a(n) = n if n is 1 or a prime, otherwise a(n) = n divided by the least prime factor of n (A032742(n)).

%C A026741 generalized to give either a prime or the largest proper divisor of a nonprime.

%C Sometimes called "Conway's subprime function", although it surely predates John Conway. - _N. J. A. Sloane_, Sep 29 2017

%H Reinhard Zumkeller, <a href="/A117818/b117818.txt">Table of n, a(n) for n = 1..10000</a>

%t Table[If[PrimeQ[n], n, If[n == 1, 1, n/FactorInteger[n][[1, 1]]]], {n, 1, 76}]

%o (Haskell)

%o a117818 n = if a010051 n == 1 then n else a032742 n

%o -- _Reinhard Zumkeller_, Jun 24 2013

%Y Cf. A026741, A032742, A292772.

%K nonn,easy

%O 1,2

%A _Roger L. Bagula_, Apr 30 2006

%E Edited by _Stefan Steinerberger_, Jul 22 2007

%E Extended by _Charles R Greathouse IV_, Jul 28 2010

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Last modified May 25 19:58 EDT 2019. Contains 323576 sequences. (Running on oeis4.)