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 A339298 #4 Dec 22 2020 18:26:08
%S A339298 1,3,26,339,6241,146261,4192048,141800728,5532432894,244530744314,
%T A339298 12076710992326,659091388208810,39390323152318533,2558571976136883890,
%U A339298 179469998189344217166,13520418589045722826274,1088748555389998857776521,93324804498600668393385498
%N A339298 Number of oriented series-parallel networks with n integer valued elements spanning an initial interval of positive integers and without multiple unit elements in parallel.
%C A339298 See A339297 for additional details.
%o A339298 (PARI) \\ See A339297 for R(n, k).
%o A339298 seq(n)={sum(k=1, n, R(n, k)*sum(r=k, n, binomial(r, k)*(-1)^(r-k)) )}
%Y A339298 Row sums of A339297.
%Y A339298 Cf. A339229.
%K A339298 nonn
%O A339298 1,2
%A A339298 _Andrew Howroyd_, Dec 22 2020