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%I #18 Jul 24 2022 03:56:00
%S 0,0,0,1,0,0,0,1,1,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,1,0,1,1,0,0,0,1,0,0,
%T 0,1,0,0,0,1,0,0,0,1,1,0,0,1,1,0,0,1,0,0,0,1,0,0,0,1,0,0,1,1,0,0,0,1,
%U 0,0,0,1,0,0,0,1,0,0,0,1,1,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,1,1,0,0,0,1,0,0,0,1,0,0,0,1,0,0,0,1,1,0,0,1,1
%N a(n) = 1 if n is divisible by the square of its smallest prime factor, 0 otherwise.
%H Antti Karttunen, <a href="/A319710/b319710.txt">Table of n, a(n) for n = 1..65537</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>.
%F a(n) = 1 iff A067029(n) > 1.
%F a(n) = 1 if A020639(n)^2 divides n, otherwise 0.
%F a(n) = 1 iff n > 1 and A126773(n) = 1.
%F a(4*n) = a(18*n + 9) = 1. - _David A. Corneth_, Oct 04 2018
%F Asymptotic mean: Limit_{m->oo} (1/m) * Sum_{k=1..m} a(k) = A283071. - _Amiram Eldar_, Jul 24 2022
%t Join[{0},Table[If[Divisible[n,FactorInteger[n][[1,1]]^2],1,0],{n,2,130}]] (* _Harvey P. Dale_, Mar 01 2019 *)
%o (PARI) A319710(n) = ((n>1)&&(factor(n)[1,2]>1));
%Y Characteristic function of A283050.
%Y Cf. A008966, A020639, A067029, A010052, A126773, A268340, A283071, A319988.
%K nonn
%O 1
%A _Antti Karttunen_, Oct 04 2018
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