A209565 Triangle of coefficients of polynomials u(n,x) jointly generated with A209566; see the Formula section.
1, 1, 1, 1, 4, 1, 1, 4, 11, 1, 1, 4, 14, 26, 1, 1, 4, 14, 45, 57, 1, 1, 4, 14, 48, 133, 120, 1, 1, 4, 14, 48, 161, 366, 247, 1, 1, 4, 14, 48, 164, 520, 952, 502, 1, 1, 4, 14, 48, 164, 557, 1604, 2371, 1013, 1, 1, 4, 14, 48, 164, 560, 1863, 4724, 5711, 2036, 1, 1, 4
Offset: 1
Examples
First five rows: 1 1...1 1...4....1 1...4....11...1 1...4...14...26...1 First three polynomials v(n,x): 1, 1 + x, 1 + 4x + x^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] + v[n - 1, x]; v[n_, x_] := 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[%] (* A209565 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A209566 *)
Formula
u(n,x)=x*u(n-1,x)+v(n-1,x),
v(n,x)=x*u(n-1,x)+2x*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.
Comments