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 A210232 #4 Mar 30 2012 18:58:16 %S A210232 1,2,2,3,5,3,4,10,10,4,5,16,25,18,5,6,24,48,54,30,6,7,33,84,123,106, %T A210232 47,7,8,44,132,246,282,194,70,8,9,56,198,438,637,594,336,100,9,10,70, %U A210232 280,730,1272,1504,1170,556,138,10,11,85,385,1140,2337,3337,3301 %N A210232 Triangle of coefficients of polynomials v(n,x) jointly generated with A210231; see the Formula section. %C A210232 First and last terms of row n are n. %C A210232 Alternating row sums: 1,0,1,0,1,0,1,0,1,0,... %C A210232 For a discussion and guide to related arrays, see A208510. %F A210232 u(n,x)=x*u(n-1,x)+v(n-1,x)+1, %F A210232 v(n,x)=(x+1)*u(n-1,x)+x*v(n-1,x)+1, %F A210232 where u(1,x)=1, v(1,x)=1. %e A210232 First five rows: %e A210232 1 %e A210232 2...2 %e A210232 3...5....3 %e A210232 4...10...10...4 %e A210232 5...16...25...16...5 %e A210232 First three polynomials v(n,x): 1, 2 + 2x , 3 + 5x + 3x^2. %t A210232 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A210232 u[n_, x_] := x*u[n - 1, x] + v[n - 1, x] + 1; %t A210232 v[n_, x_] := (x + 1)*u[n - 1, x] + x*v[n - 1, x] + 1; %t A210232 Table[Expand[u[n, x]], {n, 1, z/2}] %t A210232 Table[Expand[v[n, x]], {n, 1, z/2}] %t A210232 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A210232 TableForm[cu] %t A210232 Flatten[%] (* A210231 *) %t A210232 Table[Expand[v[n, x]], {n, 1, z}] %t A210232 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A210232 TableForm[cv] %t A210232 Flatten[%] (* A210232 *) %Y A210232 Cf. A210231, A208510. %K A210232 nonn,tabl %O A210232 1,2 %A A210232 _Clark Kimberling_, Mar 20 2012