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 A381773 #13 Mar 07 2025 10:48:57
%S A381773 1,2,15,157,1913,25427,357546,5229980,78765793,1213181593,19021747383,
%T A381773 302595975502,4871780511910,79232327379407,1299767617080662,
%U A381773 21481625997258747,357350097625089497,5978708468143961925,100537111802285439375,1698302173359384479307
%N A381773 Expansion of ( (1/x) * Series_Reversion( x/((1+x) * C(x))^3 ) )^(1/3), where C(x) is the g.f. of A000108.
%F A381773 G.f. A(x) satisfies A(x) = (1 + x*A(x)^3) * C(x*A(x)^3).
%F A381773 a(n) = Sum_{k=0..n} binomial(3*n+2*k+1,k) * binomial(3*n+1,n-k)/(3*n+2*k+1).
%o A381773 (PARI) my(N=30, x='x+O('x^N)); Vec((serreverse(x/((1+x)*(1-sqrt(1-4*x))/(2*x))^3)/x)^(1/3))
%Y A381773 Cf. A054727, A060941, A381772, A381774, A381775.
%Y A381773 Cf. A212071, A381782, A381783.
%Y A381773 Cf. A234461, A381779, A381780, A381786.
%Y A381773 Cf. A000108.
%K A381773 nonn
%O A381773 0,2
%A A381773 _Seiichi Manyama_, Mar 07 2025