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 A366582 #9 Oct 14 2023 11:29:19 %S A366582 3,8,11,12,31,43,47,59,62,107,382,514,734,811 %N A366582 Numbers k such that 6^k + 1 is a semiprime. %e A366582 11 is in this sequence because 6^11+1 = 7*51828151 is a semiprime. %Y A366582 Cf. A062394, A001358, A004062, A092559. %K A366582 nonn,more %O A366582 1,1 %A A366582 _Sean A. Irvine_, Oct 13 2023