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 A067304 #21 Apr 21 2025 02:40:14 %S A067304 1,2,1,9,5,4,64,36,32,28,584,328,300,284,256,6144,3440,3184,3072,2960, %T A067304 2704,70576,39408,36704,35680,34896,33872,31168,859520,478912,447744, %U A067304 436928,429760,422592,411776,380608,10909440,6068480,5687872,5563200,5487488,5421952,5346240,5221568,4840960 %N A067304 Generalized Catalan triangle A067298 with row reversion. %C A067304 Identity for each row n >= 1: T(n, m) + T(n, n-m+1) = A067297(n+1) (convolution of generalized Catalan numbers) for every m = 1..floor((n+1)/2). E.g., T(2*k+1, k+1) = A067297(2*(k+1))/2. %F A067304 T(n, m) = A067298(n, n-m), n >= m >= 0, otherwise 0. %F A067304 G.f. for column m >= 1 (without leading zeros): (2^(2*ceiling(m/2))*p(m, y)*(y^3)/(1+y)^4, where y = y(x) = c(4*x), with c(x) = g.f. of A000108 (Catalan) and the row polynomials p(n, y) = Sum_{k=0..n} A067329(n, k)*y^k, n >= 1. For m = 0: ((y*(3+y))^2)/(1+y)^4 with y = y(x) = c(4*x) (see A067297). %e A067304 Triangle begins: %e A067304 1; %e A067304 2, 1; %e A067304 9, 5, 4; %e A067304 64, 36, 32, 28; %e A067304 584, 328, 300, 284, 256; %e A067304 ... %e A067304 n=3: T(3, 0) = 64 = 36+28 = 32+32. %Y A067304 The columns give for m=0..4: A067297 (diagonals of A067298), A067305, A067306, A067307, A067308. %Y A067304 Cf. A067302 (row sums), A067323 (corresponding triangle for ordinary Catalan numbers). %Y A067304 Cf. A000108, A067298, A067329. %K A067304 nonn,tabl %O A067304 0,2 %A A067304 _Wolfdieter Lang_, Feb 05 2002 %E A067304 More terms from _Jinyuan Wang_, Apr 20 2025