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A208913 Triangle of coefficients of polynomials u(n,x) jointly generated with A208914; see the Formula section. 3
1, 1, 2, 1, 6, 4, 1, 12, 12, 8, 1, 20, 24, 40, 16, 1, 30, 40, 120, 80, 32, 1, 42, 60, 280, 240, 224, 64, 1, 56, 84, 560, 560, 896, 448, 128, 1, 72, 112, 1008, 1120, 2688, 1792, 1152, 256, 1, 90, 144, 1680, 2016, 6720, 5376, 5760, 2304, 512, 1, 110, 180 (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..58.

FORMULA

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

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

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

EXAMPLE

First five rows:

1

1...2

1...6....4

1...12...12...8

1...20...24...40...16

First five polynomials u(n,x):

1

1 + 2x

1 + 6x + 4x^2

1 + 12x + 12x^2 + 8x^3

1 + 20x + 24x^2 + 40x^3 + 16x^4

MATHEMATICA

u[n_, x_] := u[n - 1, x] + 2 x*v[n - 1, x];

v[n_, x_] := 2 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[%]    (* A208913 *)

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

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

TableForm[cv]

Flatten[%]    (* A208914 *)

CROSSREFS

Cf. A208914, A208510.

Sequence in context: A051482 A208923 A185045 * A208911 A208761 A123519

Adjacent sequences:  A208910 A208911 A208912 * A208914 A208915 A208916

KEYWORD

nonn,tabl

AUTHOR

Clark Kimberling, Mar 03 2012

STATUS

approved

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Last modified December 15 09:05 EST 2019. Contains 329995 sequences. (Running on oeis4.)