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 A209762 #8 Apr 15 2012 03:45:24 %S A209762 1,2,2,3,5,4,4,10,14,8,5,17,34,36,16,6,26,68,104,88,32,7,37,120,240, %T A209762 296,208,64,8,50,194,480,776,800,480,128,9,65,294,868,1736,2352,2080, %U A209762 1088,256,10,82,424,1456,3472,5824,6784,5248,2432,512,11,101,588 %N A209762 Triangle of coefficients of polynomials v(n,x) jointly generated with A209761; see the Formula section. %C A209762 Column 1: 1,2,3,4,5,6,7,8,... %C A209762 Column 2: 1+1, 1+2^2, 1+3^2, 1+4^2,... %C A209762 Last term in row n: 2^(n-1) %C A209762 Alternating row sums: 1,0,2,0,2,0,2,0,2,0,2,0,... %C A209762 For a discussion and guide to related arrays, see A208510. %F A209762 u(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x), %F A209762 v(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x)+1, %F A209762 where u(1,x)=1, v(1,x)=1. %e A209762 First five rows: %e A209762 1 %e A209762 2...2 %e A209762 3...5....4 %e A209762 4...10...14...8 %e A209762 5...17...34...36...16 %e A209762 First three polynomials v(n,x): 1, 2 + 2x , 3 + 5x + 4x^2. %t A209762 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A209762 u[n_, x_] := x*u[n - 1, x] + (x + 1)*v[n - 1, x]; %t A209762 v[n_, x_] := x*u[n - 1, x] + (x + 1)*v[n - 1, x] + 1; %t A209762 Table[Expand[u[n, x]], {n, 1, z/2}] %t A209762 Table[Expand[v[n, x]], {n, 1, z/2}] %t A209762 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A209762 TableForm[cu] %t A209762 Flatten[%] (* A209761 *) %t A209762 Table[Expand[v[n, x]], {n, 1, z}] %t A209762 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A209762 TableForm[cv] %t A209762 Flatten[%] (* A209762 *) %Y A209762 Cf. A209761, A208510. %K A209762 nonn,tabl %O A209762 1,2 %A A209762 _Clark Kimberling_, Mar 14 2012