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 A209774 #5 Mar 30 2012 18:58:15 %S A209774 1,2,3,2,7,8,3,12,25,21,3,19,56,84,55,4,26,103,227,269,144,4,36,169, %T A209774 486,848,833,377,5,45,259,914,2078,2999,2518,987,5,58,372,1565,4393, %U A209774 8277,10192,7475,2584,6,69,518,2503,8342,19420,31269,33600,21881 %N A209774 Triangle of coefficients of polynomials v(n,x) jointly generated with A209773; see the Formula section. %C A209774 Last term in row n: F(2n), where F=A000045, the Fibonacci numbers %C A209774 For a discussion and guide to related arrays, see A208510. %F A209774 u(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x), %F A209774 v(n,x)=(x+1)*u(n-1,x)+2x*v(n-1,x)+1, %F A209774 where u(1,x)=1, v(1,x)=1. %e A209774 First five rows: %e A209774 1 %e A209774 2...3 %e A209774 2...7....8 %e A209774 3...12...25...21 %e A209774 3...19...56...84...55 %e A209774 First three polynomials v(n,x): 1, 2 + 3x , 2 + 7x + 8x^2. %t A209774 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A209774 u[n_, x_] := x*u[n - 1, x] + (x + 1)*v[n - 1, x]; %t A209774 v[n_, x_] := (x + 1)*u[n - 1, x] + 2 x*v[n - 1, x] + 1; %t A209774 Table[Expand[u[n, x]], {n, 1, z/2}] %t A209774 Table[Expand[v[n, x]], {n, 1, z/2}] %t A209774 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A209774 TableForm[cu] %t A209774 Flatten[%] (* A209773 *) %t A209774 Table[Expand[v[n, x]], {n, 1, z}] %t A209774 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A209774 TableForm[cv] %t A209774 Flatten[%] (* A209774 *) %Y A209774 Cf. A209673, A208510. %K A209774 nonn,tabl %O A209774 1,2 %A A209774 _Clark Kimberling_, Mar 15 2012