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 A209704 #6 Jul 12 2012 00:40:00 %S A209704 1,3,1,4,3,2,5,6,8,3,6,10,18,14,5,7,15,33,38,27,8,8,21,54,81,83,49,13, %T A209704 9,28,82,150,197,170,89,21,10,36,118,253,401,448,342,159,34,11,45,163, %U A209704 399,736,999,987,671,282,55,12,55,218,598,1253,1988,2387,2106 %N A209704 Triangle of coefficients of polynomials v(n,x) jointly generated with A209703; see the Formula section. %C A209704 For n>1, row n starts with n+1, followed by the n-th %C A209704 triangular number, and ends in F(n+1), where F=A000045 %C A209704 (Fibonacci numbers). %C A209704 Column 3: A166830. %C A209704 Row sums: A048654. %C A209704 Alternating row sums: 1,2,3,4,5,6,7,8,9,... %C A209704 For a discussion and guide to related arrays, see A208510. %F A209704 u(n,x)=x*u(n-1,x)+x*v(n-1,x), %F A209704 v(n,x)=(x+1)*u(n-1,x)+v(n-1,x)+1, %F A209704 where u(1,x)=1, v(1,x)=1. %e A209704 First five rows: %e A209704 1 %e A209704 3...1 %e A209704 4...3....2 %e A209704 5...6....8....3 %e A209704 6...10...18...14...5 %e A209704 First three polynomials v(n,x): 1, 3 + x , 4 + 3x + 2x^2. %t A209704 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A209704 u[n_, x_] := x*u[n - 1, x] + x*v[n - 1, x]; %t A209704 v[n_, x_] := (x + 1)*u[n - 1, x] + v[n - 1, x] + 1; %t A209704 Table[Expand[u[n, x]], {n, 1, z/2}] %t A209704 Table[Expand[v[n, x]], {n, 1, z/2}] %t A209704 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A209704 TableForm[cu] %t A209704 Flatten[%] (* A209703 *) %t A209704 Table[Expand[v[n, x]], {n, 1, z}] %t A209704 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A209704 TableForm[cv] %t A209704 Flatten[%] (* A209704 *) %Y A209704 Cf. A209703, A208510. %K A209704 nonn,tabl %O A209704 1,2 %A A209704 _Clark Kimberling_, Mar 12 2012