A209749 Triangle of coefficients of polynomials u(n,x) jointly generated with A209750; see the Formula section.
1, 1, 2, 2, 4, 3, 2, 8, 9, 4, 3, 11, 21, 17, 5, 3, 17, 37, 47, 29, 6, 4, 21, 63, 101, 95, 46, 7, 4, 29, 93, 193, 241, 178, 69, 8, 5, 34, 138, 329, 519, 522, 314, 99, 9, 5, 44, 186, 533, 999, 1264, 1050, 527, 137, 10, 6, 50, 255, 805, 1776, 2710, 2845, 1991, 848
Offset: 1
Examples
First five rows: 1 1...2 2...4....3 2...8....9....4 3...11...21...17...5 First three polynomials u(n,x): 1, 1 + 2x, 2 + 4x + 3x^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_] := 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[%] (* A209749 *) Table[Expand[v[n, x]], {n, 1, z}] cv = Table[CoefficientList[v[n, x], x], {n, 1, z}]; TableForm[cv] Flatten[%] (* A209750 *)
Formula
u(n,x)=x*u(n-1,x)+(x+1)*v(n-1,x),
v(n,x)=u(n-1,x)+x*v(n-1,x)+1,
where u(1,x)=1, v(1,x)=1.
Comments