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 A210874 #9 Oct 26 2024 04:57:18 %S A210874 1,2,3,3,5,4,4,7,7,7,5,9,10,12,11,6,11,13,17,19,18,7,13,16,22,27,31, %T A210874 29,8,15,19,27,35,44,50,47,9,17,22,32,43,57,71,81,76,10,19,25,37,51, %U A210874 70,92,115,131,123,11,21,28,42,59,83,113,149,186,212,199,12,23,31 %N A210874 Triangular array U(n,k) of coefficients of polynomials defined in Comments. %C A210874 Polynomials u(n,k) are defined by u(n,x)=x*u(n-1,x)+(x^2)*u(n-2,x)+n*(x+1), where u(1)=1 and u(2,x)=3x+2. The array (U(n,k)) is defined by rows: %C A210874 u(n,x)=U(n,1)+U(n,2)*x+...+U(n,n-1)*x^(n-1). %C A210874 In each column, the first number is a Lucas number and the difference between each two consecutive terms is a Fibonacci number (see the Formula section). %C A210874 Alternating row sums: 1,-2,3,-5,8,-13,21,... (signed Fibonacci numbers) %F A210874 Column k consists of the partial sums of the following sequence: L(k), F(k+1), F(k+1), F(k+1), F(k+1),..., where L=A000032 (Lucas numbers) and F=A000045 (Fibonacci numbers). That is, U(n+1,k)-U(n,k)=F(k+1) for n>1. %e A210874 First six rows: %e A210874 1 %e A210874 2...3 %e A210874 3...5...4 %e A210874 4...7...7....7 %e A210874 5...9...10...12...11 %e A210874 6...11..13...17...19...18 %e A210874 First three polynomials u(n,x): 1, 2 + 3x, 3 + 5x + 4x^2. %t A210874 u[1, x_] := 1; u[2, x_] := 3 x + 2; z = 14; %t A210874 u[n_, x_] := x*u[n - 1, x] + (x^2)*u[n - 2, x] + n*(x + 1); %t A210874 Table[Expand[u[n, x]], {n, 1, z/2}] %t A210874 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A210874 TableForm[cu] %t A210874 Flatten[%] (* A210874 *) %Y A210874 Cf. A208510, A210881, A210875, A210880. %K A210874 nonn,tabl %O A210874 1,2 %A A210874 _Clark Kimberling_, Mar 30 2012