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 A163798 #31 Jul 05 2025 11:24:28 %S A163798 2,5,462,530,6021,14686,19537,67161,1766014,1921621,2779501 %N A163798 a(n) is the n-th J_18-prime (Josephus_18 prime). %C A163798 Place the numbers 1..N (N>=2) on a circle and cyclicly mark the 18th unmarked number until all N numbers are marked. The order in which the N numbers are marked defines a permutation; N is a J_18-prime if this permutation consists of a single cycle of length N. %C A163798 There are 8 J_18-primes in the interval 2..1000000 only. No formula is known; the J_18-primes were found by exhaustive search. %D A163798 R. L. Graham, D. E. Knuth & O. Patashnik, Concrete Mathematics (1989), Addison-Wesley, Reading, MA. Sections 1.3 & 3.3. %H A163798 P. R. J. Asveld, <a href="http://dx.doi.org/10.1016/j.dam.2011.07.019">Permuting Operations on Strings and Their Relation to Prime Numbers</a>, Discrete Applied Mathematics 159 (2011) 1915-1932. %H A163798 P. R. J. Asveld, <a href="https://citeseerx.ist.psu.edu/pdf/9d8542763057ef03a22b57f87085d69497ddaf46">Permuting Operations on Strings-Their Permutations and Their Primes</a>, Twente University of Technology, 2014. <a href="http://doc.utwente.nl/67513">University link</a>. %H A163798 <a href="/index/J#Josephus">Index entries for sequences related to the Josephus Problem</a> %e A163798 2 is a J_18-prime (trivial). %Y A163798 Cf. A163782 through A163797 for J_2- through J_17-primes. %Y A163798 Cf. A163799 through A163800 for J_19- through J_20-primes. %K A163798 nonn,more %O A163798 1,1 %A A163798 _Peter R. J. Asveld_, Aug 04 2009 %E A163798 a(9)-a(11) from _Jinyuan Wang_, Jul 05 2025