%I #25 Jul 23 2025 09:07:07

%S 1,0,1,2,7,32,177,1148,8535,71552,668037,6877742,77448741,947342072,

%T 12512378625,177525399952,2693306735145,43516930747192,

%U 746123462304725,13531269497675506,258807528403312427,5206929233591435496,109929366336996502793,2430108139669253103756

%N a(0) = 1, a(1) = 0; a(n) = a(n-2) + Sum_{k=0..n-1} k * a(k) * a(n-1-k).

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

%o (PARI) a_vector(n) = my(v=vector(n+1)); v[1]=1; for(i=2, n, v[i+1]=v[i-1]+sum(j=0, i-1, j*v[j+1]*v[i-j])); v;

%Y Cf. A075834, A386467.

%Y Cf. A082582.

%K nonn

%O 0,4

%A _Seiichi Manyama_, Jul 22 2025