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 A209154 #5 Mar 30 2012 18:58:15 %S A209154 1,2,1,4,5,2,7,14,10,2,11,32,36,18,4,16,65,104,82,32,4,22,121,258,282, %T A209154 168,52,8,29,210,574,820,676,328,88,8,37,344,1176,2116,2264,1504,608, %U A209154 136,16,46,537,2256,4980,6640,5672,3136,1096,224,16,56,805 %N A209154 Triangle of coefficients of polynomials u(n,x) jointly generated with A209157; see the Formula section. %C A209154 Last number in each row is a power of 2. %C A209154 Alternating row sums: 1,1,1,1,1,1,1,1,1,1,1,1,1,1,... %C A209154 For a discussion and guide to related arrays, see A208510. %F A209154 u(n,x)=u(n-1,x)+(x+1)*v(n-1,x), %F A209154 v(n,x)=2x*u(n-1,x)+v(n-1,x)+1, %F A209154 where u(1,x)=1, v(1,x)=1. %e A209154 First five rows: %e A209154 1 %e A209154 2....1 %e A209154 4....5....2 %e A209154 7....14...10...2 %e A209154 11...32...36...18...4 %e A209154 First three polynomials v(n,x): 1, 2 + x, 4 + 5x + 2x^2. %t A209154 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A209154 u[n_, x_] := u[n - 1, x] + (x + 1)*v[n - 1, x]; %t A209154 v[n_, x_] := 2 x*u[n - 1, x] + v[n - 1, x] + 1; %t A209154 Table[Expand[u[n, x]], {n, 1, z/2}] %t A209154 Table[Expand[v[n, x]], {n, 1, z/2}] %t A209154 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A209154 TableForm[cu] %t A209154 Flatten[%] (* A209154 *) %t A209154 Table[Expand[v[n, x]], {n, 1, z}] %t A209154 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A209154 TableForm[cv] %t A209154 Flatten[%] (* A209157 *) %Y A209154 Cf. A209157, A208510. %K A209154 nonn,tabl %O A209154 1,2 %A A209154 _Clark Kimberling_, Mar 07 2012