Geodesic
Some thoughts on pseudoprimes
Bulletin de l'Académie serbe des sciences. Classe des sciences mathématiques et naturelles, Tome 46 (2021) no. 1 
Carl Pomerance; Samuel S. Wagstaff Jr. Some thoughts on pseudoprimes. Bulletin de l'Académie serbe des sciences. Classe des sciences mathématiques et naturelles, Tome 46 (2021) no. 1. http://geodesic.mathdoc.fr/item/BASS_2021_46_1_a3/
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     title = {Some thoughts on pseudoprimes},
     journal = {Bulletin de l'Acad\'emie serbe des sciences. Classe des sciences math\'ematiques et naturelles},
     pages = {53 - 72},
     year = {2021},
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     url = {http://geodesic.mathdoc.fr/item/BASS_2021_46_1_a3/}
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Voir la notice de l'article provenant de la source eLibrary of Mathematical Institute of the Serbian Academy of Sciences and Arts

We consider several problems about pseudoprimes. First, we look at the issue of their distribution in residue classes. There is a literature on this topic in the case that the residue class is coprime to the modulus. Here we provide some robust statistics in both these cases and the general case. In particular we tabulate all even pseudoprimes to $10^{16}$. Second, we prove a recent conjecture of Ordowski: the set of integers $n$ which are a pseudoprime to some base which is a proper divisor of $n$ has an asymptotic density.