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 A208522 #5 Mar 30 2012 18:58:13 %S A208522 1,1,1,1,2,3,1,3,6,5,1,4,9,12,11,1,5,12,21,30,21,1,6,15,32,57,64,43,1, %T A208522 7,18,45,92,133,146,85,1,8,21,60,135,232,329,316,171,1,9,24,77,186, %U A208522 365,612,765,694,341,1,10,27,96,245,536,1015,1512,1801,1496,683 %N A208522 Triangle of coefficients of polynomials u(n,x) jointly generated with A208522; see the Formula section. %F A208522 u(n,x)=u(n-1,x)+x*v(n-1,x), %F A208522 v(n,x)=2x*u(n-1,x)+x*v(n-1,x)+1, %F A208522 where u(1,x)=1, v(1,x)=1. %e A208522 First five rows: %e A208522 1 %e A208522 1...1 %e A208522 1...2...3 %e A208522 1...3...6...5 %e A208522 1...4...9...12...11 %e A208522 First five polynomials u(n,x): %e A208522 1 %e A208522 1 + x %e A208522 1 + 2x + 3x^2 %e A208522 1 + 3x + 6x^2 + 5x^3 %e A208522 1 + 4x + 9x^2 + 12x^3 + 11x^4 %t A208522 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A208522 u[n_, x_] := u[n - 1, x] + x*v[n - 1, x]; %t A208522 v[n_, x_] := 2 x*u[n - 1, x] + x*v[n - 1, x] + 1; %t A208522 Table[Expand[u[n, x]], {n, 1, z/2}] %t A208522 Table[Expand[v[n, x]], {n, 1, z/2}] %t A208522 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A208522 TableForm[cu] %t A208522 Flatten[%] (* A208522 *) %t A208522 Table[Expand[v[n, x]], {n, 1, z}] %t A208522 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A208522 TableForm[cv] %t A208522 Flatten[%] (* A208523 *) %Y A208522 Cf. A208523. %K A208522 nonn,tabl %O A208522 1,5 %A A208522 _Clark Kimberling_, Feb 29 2012