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 A209134 #9 Sep 08 2013 19:59:31 %S A209134 1,0,4,0,4,10,0,4,18,28,0,4,26,72,76,0,4,34,132,256,208,0,4,42,208, %T A209134 572,864,568,0,4,50,300,1056,2272,2808,1552,0,4,58,408,1740,4800,8496, %U A209134 8896,4240,0,4,66,532,2656,8880,20208,30432,27648,11584,0,4,74 %N A209134 Triangle of coefficients of polynomials v(n,x) jointly generated with A209133; see the Formula section. %C A209134 For a discussion and guide to related arrays, see A208510. %C A209134 As triangle T(n,k) with 0<=k<=n, it is (0, 1, 0, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (4, -3/2, -1/2, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - _Philippe Deléham_, Apr 10 2012 %F A209134 u(n,x)=u(n-1,x)+(x+1)*v(n-1,x), %F A209134 v(n,x)=2x*u(n-1,x)+2x*v(n-1,x), %F A209134 where u(1,x)=1, v(1,x)=1. %F A209134 T(n,k) = T(n-1,k) + 2*T(n-1,k-1) + 2*T(n-2,k-2), T(1,0) = 1, T(2,0) = 0, T(2,1) = 4 and T(n,k) = 0 if k<0 or if k>=n. - _Philippe Deléham_, Apr 10 2012 %e A209134 First five rows: %e A209134 1 %e A209134 0...4 %e A209134 0...4...10 %e A209134 0...4...18...28 %e A209134 0...4...26...72...76 %e A209134 First three polynomials v(n,x): 1, 4x, 4x + 10x^2. %t A209134 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A209134 u[n_, x_] := u[n - 1, x] + (x + 1)*v[n - 1, x]; %t A209134 v[n_, x_] := 2 x*u[n - 1, x] + 2 x*v[n - 1, x]; %t A209134 Table[Expand[u[n, x]], {n, 1, z/2}] %t A209134 Table[Expand[v[n, x]], {n, 1, z/2}] %t A209134 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A209134 TableForm[cu] %t A209134 Flatten[%] (* A209133 *) %t A209134 Table[Expand[v[n, x]], {n, 1, z}] %t A209134 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A209134 TableForm[cv] %t A209134 Flatten[%] (* A209134 *) %Y A209134 Cf. A209133, A208510. %K A209134 nonn,tabl %O A209134 1,3 %A A209134 _Clark Kimberling_, Mar 05 2012