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A209767 Triangle of coefficients of polynomials u(n,x) jointly generated with A209768; see the Formula section. 3
1, 1, 2, 2, 6, 5, 3, 12, 20, 12, 4, 21, 52, 63, 29, 5, 33, 109, 199, 187, 70, 6, 48, 200, 490, 700, 536, 169, 7, 66, 334, 1032, 1988, 2322, 1498, 408, 8, 87, 520, 1948, 4742, 7488, 7378, 4109, 985, 9, 111, 767, 3388, 10004, 19992, 26664, 22685, 11109 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

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

LINKS

Table of n, a(n) for n=1..54.

FORMULA

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

v(n,x)=2x*u(n-1,x)+(x+1)*v(n-1,x)+1,

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

EXAMPLE

First five rows:

1

1...2

2...6....5

3...12...20...12

4...21...52...63...29

First three polynomials u(n,x): 1, 1 + 2x, 2 + 6x + 5x^2.

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_] := 2 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[%]    (* A209767 *)

Table[Expand[v[n, x]], {n, 1, z}]

cv = Table[CoefficientList[v[n, x], x], {n, 1, z}];

TableForm[cv]

Flatten[%]    (* A209768 *)

CROSSREFS

Cf. A209768, A208510.

Sequence in context: A064766 A019749 A209773 * A122070 A181661 A144160

Adjacent sequences:  A209764 A209765 A209766 * A209768 A209769 A209770

KEYWORD

nonn,tabl

AUTHOR

Clark Kimberling, Mar 15 2012

STATUS

approved

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Last modified October 17 06:08 EDT 2019. Contains 328106 sequences. (Running on oeis4.)