A209751 Triangle of coefficients of polynomials u(n,x) jointly generated with A209752; see the Formula section.
1, 1, 2, 2, 5, 4, 2, 10, 15, 8, 3, 14, 35, 39, 16, 3, 22, 63, 108, 95, 32, 4, 27, 109, 235, 309, 223, 64, 4, 38, 160, 454, 782, 838, 511, 128, 5, 44, 242, 770, 1688, 2408, 2183, 1151, 256, 5, 58, 322, 1264, 3226, 5776, 7009, 5512, 2559, 512, 6, 65, 450
Offset: 1
Examples
First five rows: 1 1...2 2...5....4 2...10...15...8 3...14...35...39...16 First three polynomials u(n,x): 1, 1 + 2x, 2 + 5x + 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 + 1)*v[n - 1, x]; v[n_, x_] := 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[%] (* A209751 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A209752 *)
Formula
u(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x),
v(n,x)=u(n-1,x)+2x*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.
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