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 A360410 #20 Sep 02 2023 11:27:40 %S A360410 1,1,2,2,1,8,4,5,12,12,7,48,24,35,75,80,37,269,114,193,404,359,174, %T A360410 1357,519,722,1664,1784,776,4995,2054 %N A360410 Number of passports of index n subgroups in PSL_2 (ZZ). %C A360410 The passports are defined as the conjugacy classes of index n subgroups in PSL_2 (ZZ) modulo the ramification degrees of the covering maps and the monodromy groups. %H A360410 D. Berghaus, H. Monien and D. Radchenko, <a href="https://arxiv.org/abs/2301.02135">A Database of Modular Forms on Noncongruence Subgroups</a>, arXiv:2301.02135 [math.NT], 2023. %H A360410 D. Berghaus, H. Monien and D. Radchenko, <a href="https://github.com/David-Berghaus/psl2z_db">A database of subgroups of PSL(2,ℤ)</a> (2023). %Y A360410 Cf. A121350, A005133. %K A360410 nonn,more %O A360410 1,3 %A A360410 _David Berghaus_, Feb 06 2023 %E A360410 Corrected by _David Berghaus_, Sep 02 2023