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A109221 A number triangle related to the Fibonacci polynomials. 2
1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 5, 3, 1, 1, 1, 7, 5, 6, 1, 1, 1, 9, 7, 15, 6, 1, 1, 1, 11, 9, 28, 15, 10, 1, 1, 1, 13, 11, 45, 28, 35, 10, 1, 1, 1, 15, 13, 66, 45, 84, 35, 15, 1, 1, 1, 17, 15, 91, 66, 165, 84, 70, 15, 1, 1, 1, 19, 17, 120, 91, 286, 165, 210, 70, 21, 1, 1, 1, 21, 19 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,9

COMMENTS

The repeated columns are made up by taking every second element of columns in A011973. Row sums are A109222.

LINKS

Table of n, a(n) for n=0..81.

FORMULA

Number triangle T(n, k)=binomial(floor((2n-k)/2)+n-k, 2n-2k)

EXAMPLE

Rows begin

1;

1,1;

1,1,1;

1,1,3,1;

1,1,5,3,1;

1,1,7,5,6,1;

CROSSREFS

Sequence in context: A081060 A255811 A131268 * A046643 A254101 A277604

Adjacent sequences:  A109218 A109219 A109220 * A109222 A109223 A109224

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry, Jun 22 2005

STATUS

approved

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Last modified September 18 10:13 EDT 2021. Contains 347518 sequences. (Running on oeis4.)