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 A053515 #10 Nov 30 2023 02:35:06 %S A053515 1,9,710,702995,9167621626,1601362624429243,3837877364912125546166, %T A053515 128777253726443722899317880176, %U A053515 61454877368531170511811727162658812448,422314689334495256777424027741114845781285378061 %N A053515 Number of connected directed 3-multigraphs on n nodes. %H A053515 Marko Riedel, <a href="/A053515/b053515.txt">Table of n, a(n) for n = 1..50</a> (first 10 terms from Vladeta Jovovic) %H A053515 Marko Riedel, <a href="/A053515/a053515.maple.txt">Maple implementation of a recurrence for the number of connected directed k-multigraphs on n nodes</a> %Y A053515 Cf. A053468, A053466. %K A053515 easy,nonn %O A053515 1,2 %A A053515 _Vladeta Jovovic_, Jan 14 2000