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 A209755 #6 Mar 30 2012 18:58:15 %S A209755 1,1,2,2,4,3,3,7,8,5,4,11,17,17,8,5,16,31,41,33,13,6,22,51,83,91,63, %T A209755 21,7,29,78,150,205,195,117,34,8,37,113,250,406,483,403,214,55,9,46, %U A209755 157,392,734,1039,1091,812,386,89,10,56,211,586,1239,2023,2536 %N A209755 Triangle of coefficients of polynomials u(n,x) jointly generated with A209756; see the Formula section. %C A209755 Column 1: 1,2,3,4,5,6,....... A000027 %C A209755 Column 2: 1,2,4,7,11,........ A000124 %C A209755 Column 3: 2,6,13,24,......... A105163 %C A209755 Final row terms: 1,2,3,5,.... A000045 (Fibonacci numbers) %C A209755 Row sums: 1,3,9,23,57,139,... A133654 %C A209755 Alternating row sums: 1,-1,1,-1,1,-1,1,-1,...; A033999 %C A209755 For a discussion and guide to related arrays, see A208510. %F A209755 u(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x), %F A209755 v(n,x)=x*u(n-1,x)+v(n-1,x)+1, %F A209755 where u(1,x)=1, v(1,x)=1. %e A209755 First five rows: %e A209755 1 %e A209755 1...2 %e A209755 2...4....3 %e A209755 3...7....8....5 %e A209755 4...11...11...17...8 %e A209755 First three polynomials u(n,x): 1, 1 + 2x, 2 + 4x + 3x^2. %t A209755 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A209755 u[n_, x_] := x*u[n - 1, x] + (x + 1)*v[n - 1, x]; %t A209755 v[n_, x_] := x*u[n - 1, x] + v[n - 1, x] + 1; %t A209755 Table[Expand[u[n, x]], {n, 1, z/2}] %t A209755 Table[Expand[v[n, x]], {n, 1, z/2}] %t A209755 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A209755 TableForm[cu] %t A209755 Flatten[%] (* A209755 *) %t A209755 Table[Expand[v[n, x]], {n, 1, z}] %t A209755 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A209755 TableForm[cv] %t A209755 Flatten[%] (* A209756 *) %t A209755 Table[u[n, x] /. x -> 1, {n, 1, z}] (* A133654 *) %t A209755 Table[v[n, x] /. x -> 1, {n, 1, z}] (* A001333 *) %t A209755 Table[u[n, x] /. x -> -1, {n, 1, z}] (* A033999 *) %t A209755 Table[v[n, x] /. x -> -1, {n, 1, z}] (* A109613 *) %Y A209755 Cf. A209756, A208510. %K A209755 nonn,tabl %O A209755 1,3 %A A209755 _Clark Kimberling_, Mar 14 2012