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 A208340 #14 Jan 22 2020 20:13:15 %S A208340 1,2,2,3,6,3,4,13,14,5,5,24,41,30,8,6,40,96,109,60,13,7,62,196,308, %T A208340 262,116,21,8,91,364,743,868,590,218,34,9,128,630,1604,2413,2240,1267, %U A208340 402,55,10,174,1032,3186,5926,7046,5424,2627,730,89,11,230,1617 %N A208340 Triangle of coefficients of polynomials v(n,x) jointly generated with A202390; see the Formula section. %C A208340 v(n,n) = F(n+1), where F=A000045, the Fibonacci numbers. %C A208340 Alternating row sums of v: (1,0,0,0,0,0,0,0,...). %C A208340 As triangle T(n,k) with 0 <= k <= n, it is (2, -1/2, 1/2, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (2, -1/2, -1/2, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. %F A208340 u(n,x) = u(n-1,x) + x*v(n-1,x), v(n,x) = (x+1)*u(n-1,x) + (x+1)*v(n-1,x), where u(1,x)=1, v(1,x)=1. %F A208340 From _Philippe Deléham_, Feb 28 2012: (Start) %F A208340 As triangle T(n,k) with 0 <= k <= n: %F A208340 T(n,k) = 2*T(n-1,k) + T(n-1,k-1) - T(n-2,k) + T(n-2,k-2) with T(0,0) = 1, T(1,0) = T(1,1) = 2 and T(n,k) = 0 if k < 0 or if k > n. %F A208340 G.f.: (1+y*x)/(1-2*x-y*x+x^2-y^2*x^2). %F A208340 Sum_{k=0..n} T(n,k)*x^k = A000007(n), A000027(n+1), A003946(n), A109115(n), A180031(n) for x = -1, 0, 1, 2, 3 respectively. (End) %e A208340 First five rows: %e A208340 1; %e A208340 2, 2; %e A208340 3, 6, 3; %e A208340 4, 13, 14, 5; %e A208340 5, 24, 41, 30, 8; %e A208340 The first five polynomials v(n,x): %e A208340 1 %e A208340 2 + 2x %e A208340 3 + 6x + 3x^2 %e A208340 4 + 13x + 14x^2 + 5x^3 %e A208340 5 + 24x + 41x^2 + 30x^3 + 8x^4 %t A208340 u[1, x_] := 1; v[1, x_] := 1; z = 13; %t A208340 u[n_, x_] := u[n - 1, x] + x*v[n - 1, x]; %t A208340 v[n_, x_] := (x + 1)*u[n - 1, x] + (x + 1)*v[n - 1, x]; %t A208340 Table[Expand[u[n, x]], {n, 1, z/2}] %t A208340 Table[Expand[v[n, x]], {n, 1, z/2}] %t A208340 cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; %t A208340 TableForm[cu] %t A208340 Flatten[%] (* A202390 *) %t A208340 Table[Expand[v[n, x]], {n, 1, z}] %t A208340 cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; %t A208340 TableForm[cv] %t A208340 Flatten[%] (* A208340 *) %t A208340 Table[u[n, x] /. x -> 1, {n, 1, z}] (* u row sums *) %t A208340 Table[v[n, x] /. x -> 1, {n, 1, z}] (* v row sums *) %t A208340 Table[u[n, x] /. x -> -1, {n, 1, z}] (* u alt. row sums *) %t A208340 Table[v[n, x] /. x -> -1, {n, 1, z}] (* v alt. row sums *) %Y A208340 Cf. A202390. %K A208340 nonn,tabl %O A208340 1,2 %A A208340 _Clark Kimberling_, Feb 27 2012