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 A366323 #9 Oct 08 2024 06:29:29 %S A366323 5,25,125,389,549,1125,12889,26925 %N A366323 Numbers k such that (k*3^k - 1)/2 is a prime. %C A366323 Odd terms of A242274. %e A366323 k = 5 is a term: (5*3^5 - 1)/2 = 607 is a prime. %Y A366323 Cf. A242274. %K A366323 nonn,hard,more %O A366323 1,1 %A A366323 _Jon E. Schoenfield_, Oct 06 2023 %E A366323 a(8) from _Michael S. Branicky_, Oct 08 2024