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 A339036 #18 Feb 26 2023 13:41:39
%S A339036 1,1,3,9,30,104,390,1518,6208,26372,116221,529341,2487054,12027502,
%T A339036 59778867,304916272,1594273763,8535706749,46753269749,261771468438,
%U A339036 1497087288210,8739579074131,52045067963540,315980654042243,1954770128712348,12315770916526091
%N A339036 Number of unlabeled connected loopless multigraphs with n edges rooted at one distinguished vertex.
%F A339036 G.f.: f(x)/g(x) where f(x) is the g.f. of A007717 and g(x) is the g.f. of A050535.
%t A339036 seq[n_] := G[2n, x+O[x]^n, {1}]/G[2n, x+O[x]^n, {}] // CoefficientList[#, x]&;
%t A339036 seq[15] (* _Jean-François Alcover_, Dec 02 2020, using _Andrew Howroyd_'s code for G in A339065 *)
%o A339036 (PARI) \\ See A339065 for G.
%o A339036 seq(n)={my(A=O(x*x^n)); Vec(G(2*n, x+A, [1])/G(2*n, x+A, []))}
%Y A339036 Cf. A007717, A050535, A076864, A339037, A339038, A339039, A339042, A339043, A339065.
%K A339036 nonn
%O A339036 0,3
%A A339036 _Andrew Howroyd_, Nov 20 2020