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Number of Carmichael numbers (A002997) less than 10^n.
61

%I #80 Jul 30 2024 08:00:33

%S 0,0,1,7,16,43,105,255,646,1547,3605,8241,19279,44706,105212,246683,

%T 585355,1401644,3381806,8220777,20138200,49679870

%N Number of Carmichael numbers (A002997) less than 10^n.

%D Richard Pinch, Carmichael Numbers up to 10^20, ANTS 7.

%D Richard G. E. Pinch, The Carmichael numbers up to 10^21, Proceedings of Conference on Algorithmic Number Theory 2007.

%H Claude Goutier, <a href="http://www-labs.iro.umontreal.ca/~goutier/OEIS/A055553/">Text file readme.text summarizing enumeration of Carmichael numbers up to 10^22.</a>

%H Claude Goutier, <a href="/A055553/a055553.txt">Text file readme.text summarizing enumeration of Carmichael numbers up to 10^22.</a> [Local copy, with permission]

%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 Claude Goutier, <a href="/A002997/a002997.7z">Compressed text file carm10e22.7z containing all the Carmichael numbers up to 10^22</a>. [Local copy, with permission. This is a very large file.]

%H Romeo Meštrović, <a href="http://arxiv.org/abs/1305.1867">Generalizations of Carmichael numbers I,</a> arXiv:1305.1867v1 [math.NT], May 4, 2013.

%H Richard G. E. Pinch, <a href="https://arxiv.org/abs/math/0504119">The Carmichael numbers up to 10^17</a>, arXiv:math/0504119 [math.NT], 2005.

%H Richard G. E. Pinch, <a href="http://arXiv.org/abs/math/0604376">The Carmichael numbers up to 10^18</a>, arXiv:math/0604376 [math.NT], 2006.

%H Richard G. E. Pinch, <a href="http://www.s369624816.websitehome.co.uk/rgep/rcam.html">Mathematics research page</a>.

%H Andrew Shallue and Jonathan Webster, <a href="https://arxiv.org/abs/2401.14495">Advances in Tabulating Carmichael Numbers</a>, arXiv:2401.14495 [math.NT], 2024.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CarmichaelNumber.html">Carmichael Number</a>.

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Pseudoprime.html">Pseudoprime</a>.

%Y Cf. A002997.

%K nonn,more

%O 1,4

%A _Eric W. Weisstein_

%E Updates from Pinch's articles sent by _Charles R Greathouse IV_, Dec 04 2005, Jul 16 2006, May 29 2007

%E a(21) from Pinch's paper by _Charles R Greathouse IV_, Feb 01 2009

%E a(22) from Shallue and Webster (2024) added by _Amiram Eldar_, Feb 23 2024

%E a(22) = 49679870 reported by _Claude Goutier_ on Dec 28 2022 (see links). - _N. J. A. Sloane_, Apr 18 2024