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 A339037 #18 Feb 26 2023 13:41:46
%S A339037 1,3,11,41,160,641,2672,11479,50938,232830,1095151,5292990,26257328,
%T A339037 133548307,695752146,3709509938,20224607541,112675185837,641016837378,
%U A339037 3721624588590,22037618432547,133023405207408,818085097509494,5123460267381837,32660335570381961,211825198708110059
%N A339037 Number of unlabeled connected loopless multigraphs with n edges rooted at one oriented edge.
%F A339037 G.f.: x*f(x)/g(x) where f(x) is the g.f. of A339065 and g(x) is the g.f. of A050535.
%t A339037 seq[n_] := Module[{A = O[x]^n}, G[2n, x+A, {1, 1}]/G[2n, x+A, {}] // CoefficientList[#, x]&]; (* _Jean-François Alcover_, Dec 02 2020, after _Andrew Howroyd_'s code for G in A339065 *)
%o A339037 (PARI) \\ See A339065 for G.
%o A339037 seq(n)={my(A=O(x*x^n)); Vec(G(2*n, x+A, [1,1])/G(2*n, x+A, []))}
%Y A339037 Cf. A050535, A076864, A339036, A339038, A339042, A339043, A339044, A339065.
%K A339037 nonn
%O A339037 1,2
%A A339037 _Andrew Howroyd_, Nov 20 2020