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A208342 Triangle of coefficients of polynomials u(n,x) jointly generated with A208343; see the Formula section. 5
1, 1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 5, 5, 1, 1, 5, 7, 10, 8, 1, 1, 6, 9, 16, 18, 13, 1, 1, 7, 11, 23, 31, 33, 21, 1, 1, 8, 13, 31, 47, 62, 59, 34, 1, 1, 9, 15, 40, 66, 101, 119, 105, 55, 1, 1, 10, 17, 50, 88, 151, 205, 227, 185, 89, 1, 1, 11, 19, 61, 113, 213, 321, 414 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

1,6

COMMENTS

coefficient of x^(n-1): A000045(n) (Fibonacci numbers).

n-th row sum:  2^(n-1)

Mirror image of triangle in A053538. - Philippe Deléham, Mar 05 2012

Subtriangle of the triangle T(n,k) given by (1, 0, -1, 1, 0, 0, 0, 0, 0, 0, 0, ...) DELTA (0, 1, 1, -1, 0, 0, 0, 0, 0, 0, 0, ...) where DELTA is the operator defined in A084938. - Philippe Deléham, Mar 12 2012

LINKS

Table of n, a(n) for n=1..75.

FORMULA

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

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

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

T(n,k) = A208747(n,k)/2^k.- Philippe Deléham, Mar 05 2012

Contribution from Philippe Deléham, Mar 12 2012 . (Start)

As DELTA-triangle T(n,k) with 0<=k<=n :

G.f.: (1-y*x+y*x^2-y^2*x^2)/(1-x-y*x+t*x^2-y^2*x^2).

T(n,k) = T(n-1,k) + T(n-1,k-1) - T(n-2,k-1) + T(n-2,k-2), T(0,0) = T(1,0) = T(2,0) = T(2,1) = 1, T(1,1) = T(2,2) = 0 and T(n,k) = 0 if k<0 or if k>n. (End)

EXAMPLE

First five rows:

1

1...1

1...1...2

1...1...3...3

1...1...4...5...5

First five polynomials u(n,x): 1, 1 + x, 1 + x + x^2, 1 + x + 3x^2 + 3x^3, 1 + x + 4x^2 + 5x^3 + 5x^4.

(1, 0, -1, 1, 0, 0, ...) DELTA (0, 1, 1, -1, 0, 0, ...) begins :

1

1, 0

1, 1, 0

1, 1, 2, 0

1, 1, 3, 3, 0

1, 1, 4, 5, 5, 0

1, 1, 5, 7, 10, 8, 0

1, 1, 6, 9, 16, 18, 13, 0

1, 1, 7, 11, 23, 31, 33, 21, 0

MATHEMATICA

u[1, x_] := 1; v[1, x_] := 1; z = 13;

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

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

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[%]  (* A208342 *)

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

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

TableForm[cv]

Flatten[%]  (* A208343 *)

CROSSREFS

Cf. A208343.

Sequence in context: A183456 A183342 A046688 * A157283 A067049 A090641

Adjacent sequences:  A208339 A208340 A208341 * A208343 A208344 A208345

KEYWORD

nonn,tabl

AUTHOR

Clark Kimberling, Feb 25 2012

STATUS

approved

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Last modified September 2 10:27 EDT 2014. Contains 246350 sequences.