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 A208515 #5 Mar 30 2012 18:58:13 %S A208515 1,1,2,1,2,3,1,2,4,5,1,2,5,8,8,1,2,6,11,15,13,1,2,7,14,23,28,21,1,2,8, %T A208515 17,32,47,51,34,1,2,9,20,42,70,93,92,55,1,2,10,23,53,97,148,181,164, %U A208515 89,1,2,11,26,65,128,217,306,346,290,144,1,2,12,29,78,163,301 %N A208515 Triangle of coefficients of polynomials v(n,x) jointly generated with A208514; see the Formula section. %F A208515 u(n,x)=u(n-1,x)+x*v(n-1,x), %F A208515 v(n,x)=x*u(n-1,x)+x*v(n-1,x)+1, %F A208515 where u(1,x)=1, v(1,x)=1. %e A208515 First five rows: %e A208515 1 %e A208515 1...2 %e A208515 1...2...3 %e A208515 1...2...4...5 %e A208515 1...2...5...8...8 %e A208515 First five polynomials v(n,x): %e A208515 1 %e A208515 1 + 2x %e A208515 1 + 2x + 3x^2 %e A208515 1 + 2x + 4x^2 + 5x^3 %e A208515 1 + 2x + 5x^2 + 8x^3 + 8x^4 %t A208515 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A208515 u[n_, x_] := u[n - 1, x] + x*v[n - 1, x]; %t A208515 v[n_, x_] := x*u[n - 1, x] + x*v[n - 1, x] + 1; %t A208515 Table[Expand[u[n, x]], {n, 1, z/2}] %t A208515 Table[Expand[v[n, x]], {n, 1, z/2}] %t A208515 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A208515 TableForm[cu] %t A208515 Flatten[%] (* A208514 *) %t A208515 Table[Expand[v[n, x]], {n, 1, z}] %t A208515 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A208515 TableForm[cv] %t A208515 Flatten[%] (* A208515 *) %Y A208515 Cf. A208514. %K A208515 nonn,tabl %O A208515 1,3 %A A208515 _Clark Kimberling_, Feb 28 2012