A394842 - OEIS

%I #8 Apr 04 2026 09:09:10

%S 1,1,4,29,290,3598,52558,876973,16393490,338723774,7659314448,

%T 188081598562,4984170966084,141791087406976,4310763278116930,

%U 139505813689497901,4788945945093822514,173832767722363540646,6653265128970512012968,267812427414947002326438

%N G.f. A(x) satisfies A(x) = 1 / (1 - x * d/dx log(1 + x*A(x)^2)).

%F G.f. A(x) satisfies A(x) = 1 + x*A(x)^2 + x^2*A(x)*d/dx(A(x)^2).

%F a(0) = 1; a(n) = Sum_{k=0..n-1} a(k)*a(n-1-k) + 2*(n-1)/3 * Sum_{i, j, k>=0 and i+j+k=n-1} a(i)*a(j)*a(k).

%Y Cf. A075834.

%K nonn

%O 0,3

%A _Seiichi Manyama_, Apr 04 2026