A209169 Triangle of coefficients of polynomials v(n,x) jointly generated with A209168; see the Formula section.
1, 2, 3, 3, 7, 7, 5, 16, 23, 17, 8, 33, 65, 70, 41, 13, 65, 159, 233, 204, 99, 21, 124, 362, 654, 776, 577, 239, 34, 231, 782, 1676, 2447, 2461, 1597, 577, 55, 423, 1627, 4018, 6937, 8586, 7534, 4348, 1393, 89, 764, 3289, 9179, 18202, 26597, 28750
Offset: 1
Examples
First five rows: 1 2 3 3 7 7 5 16 23 17 8 33 65 70 41 First three polynomials v(n,x): 1, 2 + 3*x, 3 + 7*x + 7*x^2.
Programs
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Mathematica
u[1, x_] := 1; v[1, x_] := 1; z = 16; u[n_, x_] := u[n - 1, x] + (x + 1)*v[n - 1, x]; v[n_, x_] := (x + 1)*u[n - 1, x] + 2 x*v[n - 1, x] + 1; 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[%] (* A209168 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A209169 *)
Formula
u(n,x)=u(n-1,x)+(x+1)*v(n-1,x),
v(n,x)=(x+1)*u(n-1,x)+2x*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.
T(n,k) = T(n-1,k) + 2*T(n-1,k-1) + T(n-2,k) + T(n-2,k-2), T(1,0) = 1, T(2,0) = 2, T(2,1) = 3, T(n,k) = 0 if k<0 or if k>=n. - Philippe Deléham, Mar 11 2012
Comments