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 A208526 #5 Mar 30 2012 18:58:13 %S A208526 1,1,1,1,2,4,1,3,8,10,1,4,12,22,28,1,5,16,36,68,76,1,6,20,52,120,200, %T A208526 208,1,7,24,70,184,376,592,568,1,8,28,90,260,608,1184,1736,1552,1,9, %U A208526 32,112,348,900,2016,3672,5072,4240,1,10,36,136,448,1256,3120 %N A208526 Triangle of coefficients of polynomials u(n,x) jointly generated with A208527; see the Formula section. %F A208526 u(n,x)=u(n-1,x)+x*v(n-1,x), %F A208526 v(n,x)=2x*u(n-1,x)+2x*v(n-1,x)+1, %F A208526 where u(1,x)=1, v(1,x)=1. %e A208526 First five rows: %e A208526 1 %e A208526 1...1 %e A208526 1...2...4 %e A208526 1...3...8....10 %e A208526 1...4...12...22...28 %e A208526 First five polynomials u(n,x): %e A208526 1 %e A208526 1 + x %e A208526 1 + 2x + 4x^2 %e A208526 1 + 3x + 8x^2 + 10x^3 %e A208526 1 + 4x + 12x^2 + 22x^3 + 28x^4 %t A208526 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A208526 u[n_, x_] := u[n - 1, x] + x*v[n - 1, x]; %t A208526 v[n_, x_] := 2 x*u[n - 1, x] + 2 x*v[n - 1, x] + 1; %t A208526 Table[Expand[u[n, x]], {n, 1, z/2}] %t A208526 Table[Expand[v[n, x]], {n, 1, z/2}] %t A208526 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A208526 TableForm[cu] %t A208526 Flatten[%] (* A208526 *) %t A208526 Table[Expand[v[n, x]], {n, 1, z}] %t A208526 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A208526 TableForm[cv] %t A208526 Flatten[%] (* A208527 *) %Y A208526 Cf. A208527. %K A208526 nonn,tabl %O A208526 1,5 %A A208526 _Clark Kimberling_, Feb 29 2012