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%I #15 Jan 01 2024 14:04:10
%S 1,3,7,8,14,15,20,23,24,26,38,41,44,59,60,65,78,83,92,114,123,132,133,
%T 135,140,143,158,167,168,177,182,188,195,203,204,209,220,224,239,246,
%U 248,249,266,284,285,286,287,297,299,334,378,381,395,413,415,420,437
%N Numbers n such that sigma(sigma(sigma(n))) == 0 (mod sigma(n)).
%H Harry J. Smith, <a href="/A067064/b067064.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Range[500],Divisible[DivisorSigma[1,DivisorSigma[1, DivisorSigma[ 1,#]]], DivisorSigma[ 1,#]]&] (* _Harvey P. Dale_, Oct 04 2017 *)
%o (PARI) { n=0; for (m=1, 10^10, if (sigma(sigma(sigma(m))) % sigma(m) == 0, write("b067064.txt", n++, " ", m); if (n==1000, return)) ) } \\ _Harry J. Smith_, May 02 2010
%K nonn
%O 1,2
%A _Benoit Cloitre_, Feb 17 2002
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