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 A210039 #8 Sep 02 2018 09:47:39 %S A210039 1,3,6,1,10,5,15,15,1,21,35,7,28,70,28,1,36,126,84,9,45,210,210,45,1, %T A210039 55,330,462,165,11,66,495,924,495,66,1,78,715,1716,1287,286,13,91, %U A210039 1001,3003,3003,1001,91,1,105,1365,5005,6435,3003,455,15,120,1820 %N A210039 Array of coefficients of polynomials u(n,x) jointly generated with A210040; see the Formula section. %C A210039 Every term is a binomial coefficient. %C A210039 Row sums: A000225 %C A210039 For a discussion and guide to related arrays, see A208510. %F A210039 u(n,x)=u(n-1,x)+v(n-1,x)+1, %F A210039 v(n,x)=x*u(n-1,x)+v(n-1,x)+1, %F A210039 where u(1,x)=1, v(1,x)=1. %F A210039 Also, writing the general term as T(n,m), %F A210039 T(n,k)=C(n,2k) for 1<=k<=floor[(n+1)/2], for n>=1. %e A210039 First eight rows: %e A210039 1 %e A210039 3 %e A210039 6....1 %e A210039 10...5 %e A210039 15...15....1 %e A210039 21...35....7 %e A210039 28...70....28...1 %e A210039 36...126...84...9 %e A210039 First five polynomials u(n,x): %e A210039 1 %e A210039 3 %e A210039 6 + x %e A210039 10 + 5x %e A210039 21 + 35x + 7x^2. %t A210039 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A210039 u[n_, x_] := u[n - 1, x] + v[n - 1, x] + 1; %t A210039 v[n_, x_] := x*u[n - 1, x] + v[n - 1, x] + 1; %t A210039 Table[Expand[u[n, x]], {n, 1, z/2}] %t A210039 Table[Expand[v[n, x]], {n, 1, z/2}] %t A210039 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A210039 TableForm[cu] %t A210039 Flatten[%] (* A210039 *) %t A210039 Table[Expand[v[n, x]], {n, 1, z}] %t A210039 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A210039 TableForm[cv] %t A210039 Flatten[%] (* A210040 *) %t A210039 Table[u[n, x] /. x -> 1, {n, 1, z}] (* A000225 *) %t A210039 Table[v[n, x] /. x -> 1, {n, 1, z}] (* A000225 *) %Y A210039 Cf. A034839, A210040, A208510. %K A210039 nonn,tabf %O A210039 1,2 %A A210039 _Clark Kimberling_, Mar 17 2012