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 A209153 #5 Mar 30 2012 18:58:15 %S A209153 1,2,1,4,5,2,7,14,11,3,11,31,38,22,5,16,60,103,93,43,8,22,106,239,298, %T A209153 212,81,13,29,175,497,802,782,459,150,21,37,274,952,1909,2393,1917, %U A209153 958,273,34,46,411,1710,4143,6410,6570,4465,1942,491,55,56,595 %N A209153 Triangle of coefficients of polynomials u(n,x) jointly generated with A208340; see the Formula section. %C A209153 Every row ends with a Fibonacci number (A000045). %C A209153 Alternating row sums: 1,1,1,1,1,1,1,1,1,1,1,1,1,1,... %C A209153 For a discussion and guide to related arrays, see A208510. %F A209153 u(n,x)=u(n-1,x)+(x+1)*v(n-1,x), %F A209153 v(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x)+1, %F A209153 where u(1,x)=1, v(1,x)=1. %e A209153 First five rows: %e A209153 1 %e A209153 2....1 %e A209153 4....5....2 %e A209153 7....14...11...3 %e A209153 11...31...38...22...5 %e A209153 First three polynomials v(n,x): 1, 2 + x, 4 + 5x + 2x^2. %t A209153 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A209153 u[n_, x_] := u[n - 1, x] + (x + 1)*v[n - 1, x]; %t A209153 v[n_, x_] := x*u[n - 1, x] + (x + 1)*v[n - 1, x] + 1; %t A209153 Table[Expand[u[n, x]], {n, 1, z/2}] %t A209153 Table[Expand[v[n, x]], {n, 1, z/2}] %t A209153 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A209153 TableForm[cu] %t A209153 Flatten[%] (* A209153 *) %t A209153 Table[Expand[v[n, x]], {n, 1, z}] %t A209153 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A209153 TableForm[cv] %t A209153 Flatten[%] (* A208340 *) %Y A209153 Cf. A208340, A208510. %K A209153 nonn,tabl %O A209153 1,2 %A A209153 _Clark Kimberling_, Mar 07 2012