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A109223 Number triangle related to the Fibonacci polynomials. 3
1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 3, 5, 1, 1, 1, 6, 5, 7, 1, 1, 1, 6, 15, 7, 9, 1, 1, 1, 10, 15, 28, 9, 11, 1, 1, 1, 10, 35, 28, 45, 11, 13, 1, 1, 1, 15, 35, 84, 45, 66, 13, 15, 1, 1, 1, 15, 70, 84, 165, 66, 91, 15, 17, 1, 1, 1, 21, 70, 210, 165, 286, 91, 120, 17, 19, 1, 1, 1, 21, 126, 210 (list; table; graph; refs; listen; history; internal format)
OFFSET

0,8

COMMENTS

Riordan array (1/(1-x),x/(1-x^2)^2). Row-reversal of number triangle A109221. Diagonals form a repeated version of A054142. Row sums are A109222. Diagonal sums are A094967.

FORMULA

T(n,k) = binomial(floor((n+k)/2)+k, 2*k)

T(n,k) = A065941(n+k,n-k) [Johannes W. Meijer, Aug 14 2011]

EXAMPLE

Rows begin

1;

1,1;

1,1,1;

1,3,1,1;

1,3,5,1,1;

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

1,6,15,7,9,1,1;

MAPLE

A109223 := proc(n, k): binomial(floor((n+k)/2)+k, 2*k) end: seq(seq(A109223(n, k), k=0..n), n=0..11); # [Johannes W. Meijer, Aug 14 2011]

CROSSREFS

Sequence in context: A016733 A060234 A131270 * A176246 A016466 A055210

Adjacent sequences:  A109220 A109221 A109222 * A109224 A109225 A109226

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Jun 22 2005

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Last modified February 16 21:51 EST 2012. Contains 205978 sequences.