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 A339230 #5 Nov 30 2020 08:57:05
%S A339230 1,3,9,32,120,490,2077,9158,41401,191232,897849,4273794,20573696,
%T A339230 99994830,490000756,2418246995,12008813611,59962351145,300864703306,
%U A339230 1516196518032,7670827035223,38946578808655,198379559337073,1013452414823740,5191372465942866,26658747310696437
%N A339230 Number of oriented series-parallel networks with integer valued elements summing to n.
%C A339230 See A339228 for additional details.
%e A339230 In the following examples elements in series are juxtaposed and elements in parallel are separated by '|'.
%e A339230 a(1) = 1: (1).
%e A339230 a(2) = 3: (2), (11), (1|1).
%e A339230 a(3) = 9: (3), (12), (21), (1(1|1)), ((1|1)1), (111), (1|2), (1|11), (1|1|1).
%o A339230 (PARI)
%o A339230 EulerT(v)={Vec(exp(x*Ser(dirmul(v,vector(#v,n,1/n))))-1, -#v)}
%o A339230 EdgeWeightedT(u)={my(Z=x*Ser(u)); my(p=Z+O(x^2)); for(n=2, #u, p=x*Ser(EulerT(Vec(p^2/(1+p)+Z)))); Vec(p)}
%o A339230 seq(n)={EdgeWeightedT(vector(n,i,1))}
%Y A339230 Cf. A339228, A339229.
%K A339230 nonn
%O A339230 1,2
%A A339230 _Andrew Howroyd_, Nov 29 2020