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 A385287 #25 Jul 23 2025 09:07:07 %S A385287 1,0,1,2,7,32,177,1148,8535,71552,668037,6877742,77448741,947342072, %T A385287 12512378625,177525399952,2693306735145,43516930747192, %U A385287 746123462304725,13531269497675506,258807528403312427,5206929233591435496,109929366336996502793,2430108139669253103756 %N A385287 a(0) = 1, a(1) = 0; a(n) = a(n-2) + Sum_{k=0..n-1} k * a(k) * a(n-1-k). %F A385287 G.f. A(x) satisfies A(x) = 1/( 1 - x^2 - x^2 * (d/dx A(x)) ). %o A385287 (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 A385287 Cf. A075834, A386467. %Y A385287 Cf. A082582. %K A385287 nonn %O A385287 0,4 %A A385287 _Seiichi Manyama_, Jul 22 2025