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%I #7 Nov 10 2020 18:35:45
%S 2,7,71,79,113,29,97,971,83,277,163,233,37,53,59,197,73,43,431,479,
%T 1597,15971,383,1277,43,431,479,1597,15971,383,1277,43,431,479,1597,
%U 15971,383,1277,43,431,479,1597,15971,383,1277,43,431,479,1597,15971,383,1277
%N Largest prime factor of number formed from a(n-1) with a 1 added at the end, a(1)=2.
%C Conjecture: The same number will never occur twice in this sequence. - Lowell
%C Disproved - cycle 43,431,479,1597,15971,383,1277 repeats starting at a(18). - Chandler
%H Harvey P. Dale, <a href="/A165978/b165978.txt">Table of n, a(n) for n = 1..1000</a>
%e Largest prime factor of 21 is 7, so next term after 2 is 7.
%t NestList[FactorInteger[10#+1][[-1,1]]&,2,60] (* _Harvey P. Dale_, Nov 10 2020 *)
%K base,nonn
%O 1,1
%A _J. Lowell_, Oct 02 2009
%E Edited and extended by _Ray Chandler_, Nov 10 2009
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