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%I #13 Jan 30 2023 03:27:35
%S 1,2,2,3,2,5,3,2,2,7,2,2,3,2,2,11,5,2,2,13,2,2,2,3,3,2,2,17,2,7,19,2,
%T 2,2,3,2,2,2,23,2,5,2,3,2,3,2,2,29,2,2,31,2,2,2,2,3,3,2,2,5,2,3,11,2,
%U 37,2,2,3,2,2,41,2,2,2,43,2,2,2,3,2,2,3
%N Smallest prime factors of powerful numbers (A001694).
%H Reinhard Zumkeller, <a href="/A258567/b258567.txt">Table of n, a(n) for n = 1..10000</a>
%F a(n) = A020639(A001694(n)).
%F a(A258599(n)) = A000040(n) and a(m) != A000040(n) for m < A258599(n).
%t Table[If[Min[(f = FactorInteger[n])[[;; , 2]]] > 1 || n == 1, f[[1, 1]], Nothing], {n, 1, 3000}] (* _Amiram Eldar_, Jan 30 2023 *)
%o (Haskell)
%o a258567 = a020639 . a001694
%Y Cf. A001694, A020639, A258599, A258568, A258569, A258570, A258571.
%K nonn
%O 1,2
%A _Reinhard Zumkeller_, Jun 06 2015
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