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 A381819 #13 Mar 08 2025 09:40:06
%S A381819 1,2,16,177,2271,31731,468614,7195295,113712012,1837457589,
%T A381819 30220139048,504212998955,8513461623355,145197727340337,
%U A381819 2497695979786842,43285207907364178,755005614380697735,13244500528948104210,233515959911770430972,4135792046643993604967
%N A381819 Expansion of ( (1/x) * Series_Reversion( x * ((1-x) / C(x))^3 ) )^(1/3), where C(x) is the g.f. of A000108.
%F A381819 G.f. A(x) satisfies A(x) = C(x*A(x)^3) / (1 - x*A(x)^3).
%F A381819 a(n) = Sum_{k=0..n} binomial(3*n+2*k+1,k) * binomial(4*n-k,n-k)/(3*n+2*k+1).
%o A381819 (PARI) my(N=30, x='x+O('x^N)); Vec((serreverse(x*((1-x)*2*x/(1-sqrt(1-4*x)))^3)/x)^(1/3))
%Y A381819 Cf. A381817, A381818, A381820.
%Y A381819 Cf. A000108, A381773.
%K A381819 nonn
%O A381819 0,2
%A A381819 _Seiichi Manyama_, Mar 07 2025