A210741 Triangle of coefficients of polynomials u(n,x) jointly generated with A210742; see the Formula section.
1, 1, 3, 1, 5, 8, 1, 7, 19, 21, 1, 9, 34, 65, 55, 1, 11, 53, 141, 210, 144, 1, 13, 76, 257, 534, 654, 377, 1, 15, 103, 421, 1111, 1905, 1985, 987, 1, 17, 134, 641, 2041, 4447, 6512, 5911, 2584, 1, 19, 169, 925, 3440, 9038, 16837, 21557, 17345, 6765, 1
Offset: 1
Examples
First five rows: 1 1...3 1...5...8 1...7...19...21 1...9...34...65...55 First three polynomials u(n,x): 1, 1+ 3x, 1 + 5x + 8x^2.
Programs
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Mathematica
u[1, x_] := 1; v[1, x_] := 1; z = 16; u[n_, x_] := 2 x*u[n - 1, x] + x*v[n - 1, x] + 1; v[n_, x_] := (x + 1)*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[%] (* A210741 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A210742 *)
Formula
u(n,x)=2x*u(n-1,x)+x*v(n-1,x)+1,
v(n,x)=(x+1)*u(n-1,x)+(x+1)*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.
Comments