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 A210739 #13 Aug 01 2025 07:10:58 %S A210739 1,1,3,1,4,8,1,4,14,21,1,4,15,46,55,1,4,15,55,145,144,1,4,15,56,196, %T A210739 444,377,1,4,15,56,208,678,1331,987,1,4,15,56,209,764,2282,3926,2584, %U A210739 1,4,15,56,209,779,2762,7499,11434,6765,1,4,15,56,209,780,2892,9804,24141,32960,17711 %N A210739 Triangle of coefficients of polynomials u(n,x) jointly generated with A210740; see the Formula section. %C A210739 Rows end with even-indexed Fibonacci numbers. %C A210739 Limiting row: A001353 %C A210739 Row sums: A003562 %C A210739 Alternating row sums: A000975 (signed) %C A210739 For a discussion and guide to related arrays, see A208510. %F A210739 u(n,x)=2x*u(n-1,x)+x*v(n-1,x)+1, %F A210739 v(n,x)=(x+1)*u(n-1,x)+x*v(n-1,x)+1, %F A210739 where u(1,x)=1, v(1,x)=1. %e A210739 First five rows: %e A210739 1 %e A210739 1 3 %e A210739 1 4 8 %e A210739 1 4 14 21 %e A210739 1 4 15 46 55 %e A210739 First three polynomials u(n,x): 1, 1 + 3*x, 1 + 4*x + 8*x^2. %t A210739 u[1, x_] := 1; v[1, x_] := 1; z = 16; %t A210739 u[n_, x_] := 2 x*u[n - 1, x] + x*v[n - 1, x] + 1; %t A210739 v[n_, x_] := (x + 1)*u[n - 1, x] + x*v[n - 1, x] + 1; %t A210739 Table[Expand[u[n, x]], {n, 1, z/2}] %t A210739 Table[Expand[v[n, x]], {n, 1, z/2}] %t A210739 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A210739 TableForm[cu] %t A210739 Flatten[%] (* A210739 *) %t A210739 Table[Expand[v[n, x]], {n, 1, z}] %t A210739 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A210739 TableForm[cv] %t A210739 Flatten[%] (* A210740 *) %Y A210739 Cf. A210740, A208510. %K A210739 nonn,tabl %O A210739 1,3 %A A210739 _Clark Kimberling_, Mar 24 2012