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 A209752 #5 Mar 30 2012 18:58:15 %S A209752 1,2,2,2,6,4,3,9,16,8,3,16,33,40,16,4,20,67,105,96,32,4,30,103,242, %T A209752 305,224,64,5,35,169,441,793,833,512,128,5,48,230,792,1664,2424,2177, %U A209752 1152,256,6,54,338,1230,3272,5736,7031,5505,2560,512,6,70,430 %N A209752 Triangle of coefficients of polynomials v(n,x) jointly generated with A209751; see the Formula section. %C A209752 For a discussion and guide to related arrays, see A208510. %F A209752 u(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x), %F A209752 v(n,x)=u(n-1,x)+2x*v(n-1,x)+1, %F A209752 where u(1,x)=1, v(1,x)=1. %e A209752 First five rows: %e A209752 1 %e A209752 2...2 %e A209752 2...6....4 %e A209752 3...9....16...8 %e A209752 3...16...33...40...16 %e A209752 First three polynomials v(n,x): 1, 2 + 2x , 2 + 6x + 4x^2. %t A209752 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A209752 u[n_, x_] := x*u[n - 1, x] + (x + 1)*v[n - 1, x]; %t A209752 v[n_, x_] := u[n - 1, x] + 2 x*v[n - 1, x] + 1; %t A209752 Table[Expand[u[n, x]], {n, 1, z/2}] %t A209752 Table[Expand[v[n, x]], {n, 1, z/2}] %t A209752 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A209752 TableForm[cu] %t A209752 Flatten[%] (* A209751 *) %t A209752 Table[Expand[v[n, x]], {n, 1, z}] %t A209752 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A209752 TableForm[cv] %t A209752 Flatten[%] (* A209752 *) %Y A209752 Cf. A209651, A208510. %K A209752 nonn,tabl %O A209752 1,2 %A A209752 _Clark Kimberling_, Mar 14 2012