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 A210877 #5 Oct 02 2013 16:26:12 %S A210877 1,0,3,0,3,4,0,2,8,5,0,2,6,17,6,0,2,5,18,31,7,0,2,5,14,47,51,8,0,2,5, %T A210877 13,41,107,78,9,0,2,5,13,35,115,218,113,10,0,2,5,13,34,98,296,407,157, %U A210877 11,0,2,5,13,34,90,276,695,709,211,12,0,2,5,13,34,89,244,750 %N A210877 Triangle of coefficients of polynomials v(n,x) jointly generated with A210876; see the Formula section. %C A210877 For n>2, each row begins with 0 and ends with n+1. If the term in row n and column k is denoted by U(n,k), then U(n,n-2)=A105163(n-1). %C A210877 Row sums: A000225 (-1+2^n) %C A210877 Alternating row sums: A137470 %C A210877 Limiting row: 0,2,5,13,34,89,..., even-indexed Fibonacci numbers %C A210877 For a discussion and guide to related arrays, see A208510. %F A210877 u(n,x)=x*u(n-1,x)+v(n-1,x)+1, %F A210877 v(n,x)=x*u(n-1,x)+x*v(n-1,x)+x, %F A210877 where u(1,x)=1, v(1,x)=1. %e A210877 First six rows: %e A210877 1 %e A210877 1...2 %e A210877 1...1...3 %e A210877 1...1...3...4 %e A210877 1...1...2...8...5 %e A210877 1...1...2...6...17...6 %e A210877 First three polynomials v(n,x): 1, 1 + 2x, 1 + x + 3x^2 %t A210877 u[1, x_] := 1; v[1, x_] := 1; z = 14; %t A210877 u[n_, x_] := x*u[n - 1, x] + v[n - 1, x] + 1; %t A210877 v[n_, x_] := x*u[n - 1, x] + x*v[n - 1, x] + x; %t A210877 Table[Expand[u[n, x]], {n, 1, z/2}] %t A210877 Table[Expand[v[n, x]], {n, 1, z/2}] %t A210877 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A210877 TableForm[cu] %t A210877 Flatten[%] (* A210876 *) %t A210877 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A210877 TableForm[cv] %t A210877 Flatten[%] (* A210877 *) %t A210877 Table[u[n, x] /. x -> 1, {n, 1, z}] (* A000225 *) %t A210877 Table[v[n, x] /. x -> 1, {n, 1, z}] (* A000225 *) %t A210877 Table[u[n, x] /. x -> -1, {n, 1, z}] (* A077973 *) %t A210877 Table[v[n, x] /. x -> -1, {n, 1, z}] (* A137470 *) %Y A210877 Cf. A210876, A208510. %K A210877 nonn,tabl %O A210877 1,3 %A A210877 _Clark Kimberling_, Mar 30 2012