A209698 Triangle of coefficients of polynomials v(n,x) jointly generated with A209697; see the Formula section.
1, 2, 2, 3, 4, 4, 4, 7, 10, 8, 5, 11, 20, 24, 16, 6, 16, 35, 54, 56, 32, 7, 22, 56, 104, 140, 128, 64, 8, 29, 84, 181, 294, 352, 288, 128, 9, 37, 120, 293, 552, 800, 864, 640, 256, 10, 46, 165, 449, 957, 1610, 2112, 2080, 1408, 512, 11, 56, 220, 659, 1562
Offset: 1
Examples
First five rows: 1 2...2 3...4....4 4...7....10...8 5...11...20...24...16 First three polynomials v(n,x): 1, 2 + 2x , 3 + 4x + 4x^2.
Programs
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Mathematica
u[1, x_] := 1; v[1, x_] := 1; z = 16; u[n_, x_] := x*u[n - 1, x] + x*v[n - 1, x]; v[n_, x_] := x*u[n - 1, x] + (x + 1)*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[%] (* A209697 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A209698 *)
Formula
u(n,x)=x*u(n-1,x)+x*v(n-1,x),
v(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.
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