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 A382404 #7 Mar 24 2025 10:22:06
%S A382404 -1,0,18,480,11550,275184,6597360,159629184,3897563670,95946708000,
%T A382404 2378998624860,59359563244800,1489281975509328,37545821365718400,
%U A382404 950601539891016000,24159023128878865920,616066120184552310150,15757649689979967739200
%N A382404 a(n) = -Sum_{k=0..n} (-1)^k * A039599(n,k)^3.
%H A382404 Pedro J. Miana, Hideyuki Ohtsuka, and Natalia Romero, <a href="http://arxiv.org/abs/1602.04347">Sums of powers of Catalan triangle numbers</a>, arXiv:1602.04347 [math.NT], 2016.
%F A382404 a(n) = ((n-1)/(2*n+1)) * binomial(2*n,n) * binomial(3*n,n).
%o A382404 (PARI) a(n) = (n-1)/(2*n+1)*binomial(2*n, n)*binomial(3*n, n);
%Y A382404 Cf. A039599.
%K A382404 sign
%O A382404 0,3
%A A382404 _Seiichi Manyama_, Mar 24 2025