login
A346569
Carmichael numbers (A002997) k such that A003961(k) is also a Carmichael number.
2
938531360353681, 6178246534322281, 518705522457928921, 7019247908645553241, 16242056799655920481, 94812683932464811561, 94986212971063089241, 408133613144935002601, 418441276466266605481, 453648717063017803081, 556606627235843071681, 1140359076998537247001
OFFSET
1,1
COMMENTS
Each of the first 17 terms has 3 distinct prime divisors. [updated Apr 22 2024]
a(6) <= 94812683932464811561. A term with 4 prime factors is 9584146525723596902470058833132261. - Daniel Suteu, Jul 24 2021
EXAMPLE
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.
CROSSREFS
Subsequence of A346568.
Sequence in context: A173405 A104835 A128446 * A349029 A052098 A172607
KEYWORD
nonn
AUTHOR
Amiram Eldar, Jul 23 2021
EXTENSIONS
a(6) verified and a(7)-a(13) calculated using using data from Claude Goutier by Amiram Eldar, Apr 22 2024
STATUS
approved