%I #9 Oct 10 2024 08:17:30

%S 2,2,2,2,3,2,2,3,2,2,2,2,2,3,2,5,2,2,3,2,2,2,3,2,2,2,3,2,2,5,2,3,2,2,

%T 2,3,5,2,2,3,2,2,2,3,2,7,2,2,2,2,5,2,3,2,2,7,2,3,2,5,2,2,3,2,2,2,3,2,

%U 2,2,3,2,2,5,2,3,2,7,2,2,3,2,2,3,2,2,7,2,3,2,2,2,3,2,11,2,5,2,3,2,2,2,3,2

%N Smallest prime factors of numbers that are not prime powers.

%H Amiram Eldar, <a href="/A074592/b074592.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = A020639(A024619(n)).

%F a(n) > 2 iff n+1 and n+2 are prime powers (A006549).

%t s[n_] := Module[{f = FactorInteger[n]}, If[Length[f] > 1, f[[1, 1]], Nothing]]; Array[s, 200] (* _Amiram Eldar_, Oct 10 2024 *)

%Y Cf. A006549, A020639, A024619, A074593, A074594, A074595.

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Aug 25 2002