This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A324317 #61 Apr 22 2024 08:12:13 %S A324317 0,0,0,2,4,9,19,51,107,219,417,757,1470,2666,5040,9280,17210,32039, %T A324317 59762,111811,210627,397968 %N A324317 Number of primary Carmichael numbers (A324316) less than 10^n. %C A324317 The number of Carmichael numbers (A002997) less than 10^n is 0, 0, 1, 7, 16, 43, 105, 255, 646, 1547, 3605, 8241, 19279, 44706, 105212, 246683, 585355, 1401644, ... (see A055553). %C A324317 The terms up to a(10) are given in Table 1 of Kellner and Sondow 2019. The terms up to a(18) and related results are given in Table 1.5 of Kellner 2019. %C A324317 All computations depend on Pinch's database. %H A324317 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 A324317 Bernd C. Kellner and Jonathan Sondow, <a href="https://doi.org/10.4169/amer.math.monthly.124.8.695">Power-Sum Denominators</a>, Amer. Math. Monthly, 124 (2017), 695-709; <a href="https://arxiv.org/abs/1705.03857">arXiv preprint</a>, arXiv:1705.03857 [math.NT], 2017. %H A324317 Bernd C. Kellner and Jonathan Sondow, <a href="http://math.colgate.edu/~integers/v52/v52.pdf">On Carmichael and polygonal numbers, Bernoulli polynomials, and sums of base-p digits</a>, Integers 21 (2021), #A52, 21 pp.; <a href="https://arxiv.org/abs/1902.10672">arXiv preprint</a>, arXiv:1902.10672 [math.NT], 2019-2021. %H A324317 Bernd C. Kellner, <a href="http://math.colgate.edu/~integers/w38/w38.pdf">On primary Carmichael numbers</a>, Integers 22 (2022), #A38, 39 pp.; <a href="https://arxiv.org/abs/1902.11283">arXiv preprint</a>, arXiv:1902.11283 [math.NT], 2019-2022. %H A324317 R. G. E. Pinch, <a href="http://www.s369624816.websitehome.co.uk/rgep/cartable.html">Tables relating to Carmichael numbers</a> (The Carmichael numbers up to 10^18, 2008). %H A324317 <a href="/index/Ca#Carmichael">Index entries for sequences related to Carmichael numbers</a>. %e A324317 There are two primary Carmichael numbers less than 10^4, namely, 1729 and 2821, so a(4) = 2. %Y A324317 Cf. A002997, A055553, A324315, A324316, A324318, A324319, A324320, A324369, A324370, A324371, A324404, A324405. %K A324317 nonn,base,more,hard %O A324317 1,4 %A A324317 _Bernd C. Kellner_ and _Jonathan Sondow_, Feb 22 2019 %E A324317 a(11)-a(18) from _Amiram Eldar_, Mar 01 2019 %E A324317 a(19) from _Amiram Eldar_, Dec 05 2020 %E A324317 a(20)-a(22) calculated using data from _Claude Goutier_ and added by _Amiram Eldar_, Apr 22 2024