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 A339229 #7 Nov 30 2020 08:56:57
%S A339229 1,5,46,677,13897,367329,11875112,453884998,20021744482,1001103144204,
%T A339229 55950350379398,3456387167052662,233868854544617505,
%U A339229 17200896572547662922,1366363690436820691346,116580486267706011046208,10633034275200701222560393,1032398637197381396948606128
%N A339229 Number of oriented series-parallel networks with n integer valued elements spanning an initial interval of positive integers.
%C A339229 See A339228 for additional details.
%e A339229 In the following examples elements in series are juxtaposed and elements in parallel are separated by '|'.
%e A339229 a(1) = 1: (1).
%e A339229 a(2) = 5: (11), (12), (21), (1|1), (1|2).
%o A339229 (PARI) \\ See A339228 for R(n,k).
%o A339229 seq(n)={sum(k=1, n, R(n, k)*sum(r=k, n, binomial(r, k)*(-1)^(r-k)) )}
%Y A339229 Row sums of A339228.
%K A339229 nonn
%O A339229 1,2
%A A339229 _Andrew Howroyd_, Nov 28 2020