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%I #19 Apr 22 2024 14:29:10
%S 938531360353681,6178246534322281,518705522457928921,
%T 7019247908645553241,16242056799655920481,94812683932464811561,
%U 94986212971063089241,408133613144935002601,418441276466266605481,453648717063017803081,556606627235843071681,1140359076998537247001
%N Carmichael numbers (A002997) k such that A003961(k) is also a Carmichael number.
%C Each of the first 17 terms has 3 distinct prime divisors. [updated Apr 22 2024]
%C a(6) <= 94812683932464811561. A term with 4 prime factors is 9584146525723596902470058833132261. - _Daniel Suteu_, Jul 24 2021
%H Amiram Eldar, <a href="/A346569/b346569.txt">Table of n, a(n) for n = 1..17</a> (terms below 10^22 calculated using data from Claude Goutier)
%H Claude Goutier, <a href="http://www-labs.iro.umontreal.ca/~goutier/OEIS/A055553/">Compressed text file carm10e22.gz containing all the Carmichael numbers up to 10^22</a>.
%H <a href="/index/Ca#Carmichael">Index entries for sequences related to Carmichael numbers</a>.
%e 938531360353681 = 53881 * 107761 * 161641 is a term since it is a Carmichael number, and A003961(938531360353681) = 53887 * 107773 * 161659 = 938844932257009 is also a Carmichael number.
%Y Cf. A002997, A003961.
%Y Subsequence of A346568.
%K nonn
%O 1,1
%A _Amiram Eldar_, Jul 23 2021
%E a(6) verified and a(7)-a(13) calculated using using data from _Claude Goutier_ by _Amiram Eldar_, Apr 22 2024
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