A209765 Triangle of coefficients of polynomials u(n,x) jointly generated with A209766; see the Formula section.
1, 1, 2, 1, 5, 5, 1, 5, 15, 12, 1, 5, 21, 45, 29, 1, 5, 21, 77, 129, 70, 1, 5, 21, 89, 265, 361, 169, 1, 5, 21, 89, 353, 865, 991, 408, 1, 5, 21, 89, 377, 1325, 2717, 2681, 985, 1, 5, 21, 89, 377, 1549, 4733, 8281, 7169, 2378, 1, 5, 21, 89, 377, 1597, 6125
Offset: 1
Examples
First five rows: 1 1...2 1...5...5 1...5...15...12 1...5...21...45...29 First three polynomials u(n,x): 1, 1 + 2x, 1 + 5x + 5x^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_] := 2 x*u[n - 1, x] + 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[%] (* A209765 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A209766 *) Table[u[n, x] /. x -> 1, {n, 1, z}] (* A081250 *) Table[v[n, x] /. x -> 1, {n, 1, z}] (* A060925 *) Table[u[n, x] /. x -> -1, {n, 1, z}] (* A033999 *) Table[v[n, x] /. x -> -1, {n, 1, z}] (* A042963 signed *)
Formula
u(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x),
v(n,x)=2x*u(n-1,x)+x*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.
Comments