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 A378078 #8 Nov 21 2024 22:26:26
%S A378078 1,1,3,12,50,219,987,4552,21366,101730,490094,2384520,11699844,
%T A378078 57825103,287611755,1438536144,7230782414,36506547918,185047345050,
%U A378078 941359362760,4804468999932,24593960996814,126239765780606,649610643221616,3350542070046300,17318377059738820
%N A378078 Number of noncrossing trees with n edges and all nodes having degree at most 3.
%H A378078 Andrew Howroyd, <a href="/A378078/b378078.txt">Table of n, a(n) for n = 0..500</a>
%F A378078 G.f.: (1 + g(x) + g(x)^2 + g(x)^3) where g(x)/x is the g.f. of A122871.
%e A378078 a(4) = A001764(4) - 5 where the 5 trees excluded are those with one node connected to the other four.
%o A378078 (PARI) seq(n)={my(g=serreverse(x/(1+2*x+3*x^2) + O(x*x^n))); Vec(1 + g + g^2 + g^3)}
%Y A378078 Cf. A001764, A122871, A378079.
%K A378078 nonn
%O A378078 0,3
%A A378078 _Andrew Howroyd_, Nov 21 2024