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 A366702 #5 Oct 17 2023 08:34:58 %S A366702 2,4,5,11,16,32,109,128,193 %N A366702 Numbers k such that 12^k + 1 is a semiprime. %e A366702 11 is in this sequence because 12^11+1 = 13*57154490053 is a semiprime. %Y A366702 Cf. A178248, A001358, A004064, A366582. %K A366702 nonn,more %O A366702 1,1 %A A366702 _Sean A. Irvine_, Oct 16 2023