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%I #20 Apr 29 2019 02:14:33
%S 168,312,528,960,2088,3762,5598,6570,10746,13254,13830,19434,20886,
%T 21606,25098,26742,26754,40446,63234,77406,110754,171486,253458,
%U 295740,647748,1077612,1467588,1956812
%N Aliquot sequence starting at 168.
%C The sum-of-divisor function A000203 and aliquot parts A001065 are defined only for positive integers, so the trajectory ends when 0 is reached, here at index 175. - _M. F. Hasler_, Feb 24 2018
%D R. K. Guy, Unsolved Problems in Number Theory, B6.
%H T. D. Noe, <a href="/A008890/b008890.txt">Table of n, a(n) for n = 0..175</a> (a(176) removed by _Georg Fischer_, Apr 28 2019)
%H Christophe Clavier, <a href="http://christophe.clavier.free.fr/Aliquot/site/Aliquot.html">Aliquot Sequences</a>
%H <a href="/index/Al#ALIQUOT">Index entries for sequences related to aliquot parts</a>.
%F a(n+1) = A001065(a(n)). - _R. J. Mathar_, Oct 11 2017
%p f := proc(n) option remember; if n = 0 then 168; else sigma(f(n-1))-f(n-1); fi; end:
%t NestList[DivisorSigma[1, #] - # &, 168, 175] (* _Alonso del Arte_, Feb 24 2018 *)
%o (PARI) a(n,a=168)={for(i=1,n,a=sigma(a)-a);a} \\ _M. F. Hasler_, Feb 24 2018
%Y Cf. A008885 (starting at 30), ..., A008892 (starting at 276), A098007 (length of aliquot sequences).
%K nonn,fini,full
%O 0,1
%A _N. J. A. Sloane_.
%E Edited by _M. F. Hasler_, Feb 24 2018
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