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 A067297 #14 Jan 08 2025 09:26:39
%S A067297 1,2,9,64,584,6144,70576,859520,10909440,142773760,1913027840,
%T A067297 26115182592,361936623616,5079287545856,72033971859456,
%U A067297 1030768222437376,14864066521333760,215791593346695168
%N A067297 Convolution of C(2,2; n) := A064340(n) (generalized Catalan numbers) with itself.
%F A067297 a(n) = Sum_{k=0..n} C(2, 2; k)*C(2, 2; n-k).
%F A067297 G.f.: ((3+c(4*x))/(2*(1-2*x*c(4*x))*(1+c(4*x))))^2, with c(x) g.f. for A000108 (Catalan). Also: (c(4*x)*(3+c(4*x)))^2/(1+c(4*x))^4, or (-1+36*x +(1+24*x)*c(4*x))/((1-4*x)*(1+20*x)*c(4*x)-1+44*x-16*x^2).
%Y A067297 Bisections: a(2*k) = A067320(k), a(2*k+1) = 2*A067321(k), k>=0.
%K A067297 nonn,easy
%O A067297 0,2
%A A067297 _Wolfdieter Lang_, Feb 05 2002