A210551 Triangle of coefficients of polynomials v(n,x) jointly generated with A172431; see the Formula section.
1, 3, 1, 5, 6, 1, 7, 15, 10, 1, 9, 28, 35, 15, 1, 11, 45, 84, 70, 21, 1, 13, 66, 165, 210, 126, 28, 1, 15, 91, 286, 495, 462, 210, 36, 1, 17, 120, 455, 1001, 1287, 924, 330, 45, 1, 19, 153, 680, 1820, 3003, 3003, 1716, 495, 55, 1, 21, 190, 969, 3060, 6188
Offset: 1
Examples
From _Paul Weisenhorn_, May 17 2020 : (Start) First five rows of v(n.x): 1 3 1 5 6 1 7 15 10 1 9 28 35 15 1 First three polynomials v(n,x): 1, 3 + x, 5 + 6x + x^2. (End) From _Paul Weisenhorn_, May 14 2020: (Start) First five rows of u(n,x): 1 1 2 1 4 3 1 6 10 4 1 8 21 20 5 First three polynomials u(n,x): 1, 1 + 2x, 1 + 4x + 3x^2. (End)
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] + 1; v[n_, 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[%] (* A172431 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A210551 *)
Formula
u(n,x)=x*u(n-1,x)+x*v(n-1,x)+1,
v(n,x)=u(n-1,x)+(x+1)*v(n-1,x)+1
where u(1,x)=1, v(1,x)=1.
Comments