A208922 Triangle of coefficients of polynomials v(n,x) jointly generated with A208921; see the Formula section.
1, 3, 1, 5, 4, 2, 7, 13, 12, 2, 9, 32, 40, 16, 4, 11, 65, 108, 80, 36, 4, 13, 116, 258, 288, 180, 48, 8, 15, 189, 560, 842, 700, 324, 96, 8, 17, 288, 1120, 2144, 2312, 1536, 640, 128, 16, 19, 417, 2088, 4944, 6728, 5832, 3232, 1088, 240, 16, 21, 580, 3666
Offset: 1
Examples
First five rows: 1 3...1 5...4....2 7...13...12...2 9...32...40...16...4 First five polynomials v(n,x): 1 3 + x 5 + 4x + 2x^2 7 + 13x + 12x^2 + 2x^3 9 + 32x + 40x^2 + 16x^3 + 4x^4
Programs
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Mathematica
u[1, x_] := 1; v[1, x_] := 1; z = 16; u[n_, x_] := u[n - 1, x] + 2x*v[n - 1, x]; v[n_, x_] := (x + 1)*u[n - 1, 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[%] (* A208921 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A208922 *)
Formula
u(n,x)=u(n-1,x)+2x*v(n-1,x),
v(n,x)=(x+1)*u(n-1,x)+v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.
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