A209688 Triangle of coefficients of polynomials v(n,x) jointly generated with A115241; see the Formula section.

1, 3, 4, 2, 5, 5, 2, 6, 9, 7, 2, 7, 14, 16, 9, 2, 8, 20, 30, 25, 11, 2, 9, 27, 50, 55, 36, 13, 2, 10, 35, 77, 105, 91, 49, 15, 2, 11, 44, 112, 182, 196, 140, 64, 17, 2, 12, 54, 156, 294, 378, 336, 204, 81, 19, 2, 13, 65, 210, 450, 672, 714, 540, 285, 100, 21, 2

Offset: 1

Author

Clark Kimberling, Mar 12 2012

Keywords

• nonn
• tabf

Comments

Alternating row sums: 1,3,2,2,2,2,2,2,2,2,2,2,...

For a discussion and guide to related arrays, see A208510.

Examples

			First five rows:
1
3...1
4...2...3
5...5...2
6...9...7...2
First three polynomials v(n,x): 1, 3 + x , 4 + 2x + 3x^2.
		

Crossrefs

Cf. A115241, A208510.

Programs

Mathematica

u[1, x_] := 1; v[1, x_] := 1; z = 16;
u[n_, x_] := x*u[n - 1, x] + x*v[n - 1, x];
v[n_, x_] := 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[%]    (* A115241 *)
Table[Expand[v[n, x]], {n, 1, z}]
cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];
TableForm[cv]
Flatten[%]   (* A209688 *)

Formula

u(n,x)=x*u(n-1,x)+x*v(n-1,x),

v(n,x)=u(n-1,x)+v(n-1,x)+1,

where u(1,x)=1, v(1,x)=1.