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 A381536 #11 Mar 08 2025 20:47:43
%S A381536 1,1,35,7350,5255250,9564555000,37072215180000,271183254041700000,
%T A381536 3430468163627505000000,70238835650273164875000000,
%U A381536 2210064963735845132791875000000,102493972758213553878355995000000000,6769214430816214165896021689775000000000,618638506832293812621237422228537250000000000
%N A381536 Number of labeled histories for rooted 4-furcating trees with 3n+1 leaves if simultaneous 4-furcations are not allowed.
%H A381536 Emily H. Dickey and Noah A. Rosenberg, <a href="https://doi.org/10.1098/rstb.2023.0307">Labelled histories with multifurcation and simultaneity</a>, Phil. Trans. R. Soc. B 380 (2025), 20230307 (see Table 1).
%F A381536 a(n) = ((3*n+1)!/24^n) * Product_{i=1..n} (3*i-2).
%p A381536 a:= n-> (3*n+1)!/24^n*mul(3*i-2, i=1..n):
%p A381536 seq(a(n), n=0..13); # _Alois P. Heinz_, Feb 26 2025
%Y A381536 Cf. A006472, A339411, A381523.
%K A381536 nonn
%O A381536 0,3
%A A381536 _Noah A Rosenberg_, Feb 26 2025