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 A027845 #8 Jul 08 2025 17:56:11 %S A027845 1,15,43,371,1321,11979 %N A027845 Number of subgroups of index n in fundamental group of a certain fiber space. %D A027845 V. A. Liskovets and A. Mednykh, Enumeration of subgroups in the fundamental groups of orientable circle bundles over surfaces, Commun. in Algebra, 28, No. 4 (2000), 1717-1738. %K A027845 nonn %O A027845 1,2 %A A027845 _N. J. A. Sloane_