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 A210040 #6 Mar 30 2012 18:58:16 %S A210040 1,2,1,3,4,4,10,1,5,20,6,6,35,21,1,7,56,56,8,8,84,126,36,1,9,120,252, %T A210040 120,10,10,165,462,330,55,1,11,220,792,792,220,12,12,286,1287,1716, %U A210040 715,78,1,13,364,2002,3432,2002,364,14,14,455,3003,6435,5005,1365 %N A210040 Array of coefficients of polynomials v(n,x) jointly generated with A210039; see the Formula section. %C A210040 Every term is a binomial coefficient. %C A210040 Row sums: A000225 %C A210040 For a discussion and guide to related arrays, see A208510. %F A210040 u(n,x)=u(n-1,x)+v(n-1,x)+1, %F A210040 v(n,x)=x*u(n-1,x)+v(n-1,x)+1, %F A210040 where u(1,x)=1, v(1,x)=1. %F A210040 Also: writing T(n,m) for the general term, %F A210040 T(n,1)=n for n>=1; %F A210040 T(n,k)=C(n+1,2k-1) for 1<=k<=floor[(n+2)/2]. %e A210040 First eight rows: %e A210040 1 %e A210040 2...1 %e A210040 3...4 %e A210040 4...10...1 %e A210040 5...20...6 %e A210040 6...35...21....1 %e A210040 7...56...56....8 %e A210040 8...84...126...36...1 %e A210040 First five polynomials v(n,x): %e A210040 1 %e A210040 2 + x %e A210040 3 + 4x. %e A210040 4 + 10x + x^2 %e A210040 5 + 20x + 6x^2. %t A210040 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A210040 u[n_, x_] := u[n - 1, x] + v[n - 1, x] + 1; %t A210040 v[n_, x_] := x*u[n - 1, x] + v[n - 1, x] + 1; %t A210040 Table[Expand[u[n, x]], {n, 1, z/2}] %t A210040 Table[Expand[v[n, x]], {n, 1, z/2}] %t A210040 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A210040 TableForm[cu] %t A210040 Flatten[%] (* A210039 *) %t A210040 Table[Expand[v[n, x]], {n, 1, z}] %t A210040 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A210040 TableForm[cv] %t A210040 Flatten[%] (* A210040 *) %t A210040 Table[u[n, x] /. x -> 1, {n, 1, z}] (* A000225 *) %t A210040 Table[v[n, x] /. x -> 1, {n, 1, z}] (* A000225 *) %Y A210040 Cf. A210039, A208510. %K A210040 nonn,tabf %O A210040 1,2 %A A210040 _Clark Kimberling_, Mar 17 2012