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 A209164 #5 Mar 30 2012 18:58:15 %S A209164 1,2,1,5,5,1,11,15,6,1,23,41,27,9,1,47,105,95,45,10,1,95,257,295,185, %T A209164 65,13,1,191,609,847,665,315,91,14,1,383,1409,2303,2177,1295,497,119, %U A209164 17,1,767,3201,6015,6657,4767,2289,735,153,18,1,1535,7169,15231 %N A209164 Triangle of coefficients of polynomials u(n,x) jointly generated with A209165; see the Formula section. %C A209164 Alternating row sums: 1,1,1,1,1,1,1,1,1,1,1,1,1,1,... %C A209164 For a discussion and guide to related arrays, see A208510. %F A209164 u(n,x)=u(n-1,x)+(x+1)*v(n-1,x), %F A209164 v(n,x)=(x+1)*u(n-1,x)+v(n-1,x)+1, %F A209164 where u(1,x)=1, v(1,x)=1. %e A209164 First five rows: %e A209164 1 %e A209164 2....1 %e A209164 5....5....1 %e A209164 11...15...6....1 %e A209164 23...41...27...9...1 %e A209164 First three polynomials v(n,x): 1, 2 + x, 5 + 5x + x^2. %t A209164 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A209164 u[n_, x_] := u[n - 1, x] + (x + 1)*v[n - 1, x]; %t A209164 v[n_, x_] := (x + 1)*u[n - 1, x] + v[n - 1, x] + 1; %t A209164 Table[Expand[u[n, x]], {n, 1, z/2}] %t A209164 Table[Expand[v[n, x]], {n, 1, z/2}] %t A209164 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A209164 TableForm[cu] %t A209164 Flatten[%] (* A209164 *) %t A209164 Table[Expand[v[n, x]], {n, 1, z}] %t A209164 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A209164 TableForm[cv] %t A209164 Flatten[%] (* A209165 *) %Y A209164 Cf. A209165, A208510. %K A209164 nonn,tabl %O A209164 1,2 %A A209164 _Clark Kimberling_, Mar 08 2012