A208329 Triangle of coefficients of polynomials v(n,x) jointly generated with A208328; see the Formula section.
1, 0, 3, 0, 2, 5, 0, 2, 4, 11, 0, 2, 4, 14, 21, 0, 2, 4, 18, 32, 43, 0, 2, 4, 22, 44, 82, 85, 0, 2, 4, 26, 56, 130, 188, 171, 0, 2, 4, 30, 68, 186, 324, 438, 341, 0, 2, 4, 34, 80, 250, 492, 834, 984, 683, 0, 2, 4, 38, 92, 322, 692, 1374, 2028, 2202, 1365, 0, 2, 4, 42
Offset: 1
Examples
First five rows:
1;
0, 3;
0, 2, 5;
0, 2, 4, 11;
0, 2, 4, 14, 21;
First five polynomials u(n,x):
1
3x
2x + 5x^2
2x + 4x^2 + 11x^3
2x + 4x^2 + 14x^3 + 21x^4.
Crossrefs
Cf. A208328.
Programs
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Mathematica
u[1, x_] := 1; v[1, x_] := 1; z = 13; u[n_, x_] := u[n - 1, x] + x*v[n - 1, x]; v[n_, x_] := 2 x*u[n - 1, x] + x*v[n - 1, x]; Table[Expand[u[n, x]], {n, 1, z/2}] Table[Expand[v[n, x]], {n, 1, z/2}] cu = Table[CoefficientList[u[n, x], x], {n, 1, z}]; TableForm[cu] Flatten[%] (* A208328 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A208329 *)
Formula
u(n,x) = u(n-1,x) + x*v(n-1,x),
v(n,x) = 2x*u(n-1,x) + x*v(n-1,x),
where u(1,x)=1, v(1,x)=1.
From Philippe Deléham, Feb 27 2012: (Start)
As triangle T(n,k), 0 <= k <= n:
T(n,k) = T(n-1,k) + T(n-1,k-1) - T(n-2,k-1) + 2*T(n-2,k-2) with T(0,0) = 1, T(1,0) = 0, T(1,1) = 3 and T(n,k) = 0 if k < 0 or if k > n.
G.f.: (1-(1-2*y)*x)/(1-(1+y)*x+y*(1-2*y)*x^2).
Comments