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 A350451 #8 Jan 09 2022 13:14:33
%S A350451 1,1,3,9,36,151,750,3959,22857,140031,909388,6202031,44256875,
%T A350451 328994157,2540242646,20317980102,167980915848,1432808198569,
%U A350451 12587788263807,113739153822878,1055610955120803,10051265993496814,98083750658261085,979961276867802001,10015362142357613001
%N A350451 Number of weakly connected acyclic digraphs with n arcs.
%H A350451 Andrew Howroyd, <a href="/A350451/b350451.txt">Table of n, a(n) for n = 0..40</a>
%o A350451 (PARI) \\ See PARI link in A122078 for program code.
%o A350451 { my(T=WeakAcyclicDigraphsTr(15)); vector(#T, n, vecsum(T[n])) }
%Y A350451 Row sums of A350450.
%Y A350451 Column sums of A350449.
%Y A350451 Cf. A101228, A122078.
%K A350451 nonn
%O A350451 0,3
%A A350451 _Andrew Howroyd_, Dec 31 2021