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 A345258 #31 Jun 09 2022 17:56:32 %S A345258 1,1,2,10,98,1960,80176,6686760,1129588960,384610774696, %T A345258 263104175114712,360908867732030980,991603865814038728388, %U A345258 5453395569997436383751204,60010050181461052836515513108,1321051495313052133670927704328040,58170762510305449187073353930875222256 %N A345258 Number of acyclic digraphs (or DAGs) on n unlabeled vertices with one source and one sink. %H A345258 Andrew Howroyd, <a href="/A345258/b345258.txt">Table of n, a(n) for n = 1..50</a> (terms 1..40 from Mikhail Tikhomirov) %H A345258 Marcel et al., <a href="https://mathoverflow.net/q/395095">Is there a formula for the number of st-dags (DAG with 1 source and 1 sink) with n vertices?</a>, MathOverflow, 2021. %o A345258 (PARI) A345258seq(16) \\ See PARI link in A122078 for program code. %Y A345258 Row sums of A350491. %Y A345258 The labeled version is A165950. %Y A345258 Cf. A003087, A049531, A122078, A350415, A350492. %K A345258 nonn %O A345258 1,3 %A A345258 _Max Alekseyev_, Jun 12 2021 %E A345258 a(9) from _Brendan McKay_. %E A345258 Terms a(10) and beyond from _Mikhail Tikhomirov_, Jun 16 2021