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 A209159 #5 Mar 30 2012 18:58:15 %S A209159 1,1,3,1,5,5,1,7,15,11,1,9,29,41,21,1,11,47,99,103,43,1,13,69,193,301, %T A209159 249,85,1,15,95,331,687,851,583,171,1,17,125,521,1349,2225,2285,1337, %U A209159 341,1,19,159,771,2391,4923,6735,5907,3015,683,1,21,197,1089 %N A209159 Triangle of coefficients of polynomials v(n,x) jointly generated with A209158; see the Formula section. %C A209159 Alternating row sums: 1,-2,1,-2,1,-2,1,-2,1,-2,... %C A209159 For a discussion and guide to related arrays, see A208510. %F A209159 u(n,x)=u(n-1,x)+(x+1)*v(n-1,x), %F A209159 v(n,x)=2x*u(n-1,x)+x*v(n-1,x)+1, %F A209159 where u(1,x)=1, v(1,x)=1. %e A209159 First five rows: %e A209159 1 %e A209159 1...3 %e A209159 1...5...5 %e A209159 1...7...15...11 %e A209159 1...9...29...41...21 %e A209159 First three polynomials v(n,x): 1, 1 + 3x, 1 + 5x + 5x^2. %t A209159 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A209159 u[n_, x_] := u[n - 1, x] + (x + 1)*v[n - 1, x]; %t A209159 v[n_, x_] := 2 x*u[n - 1, x] + x*v[n - 1, x] + 1; %t A209159 Table[Expand[u[n, x]], {n, 1, z/2}] %t A209159 Table[Expand[v[n, x]], {n, 1, z/2}] %t A209159 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A209159 TableForm[cu] %t A209159 Flatten[%] (* A209158 *) %t A209159 Table[Expand[v[n, x]], {n, 1, z}] %t A209159 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A209159 TableForm[cv] %t A209159 Flatten[%] (* A209159 *) %Y A209159 Cf. A209158, A208510. %K A209159 nonn,tabl %O A209159 1,3 %A A209159 _Clark Kimberling_, Mar 07 2012