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A108756 A triangle related to the Jacobsthal polynomials. 2
1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 1, 4, 5, 1, 1, 3, 6, 6, 7, 1, 1, 1, 10, 15, 8, 9, 1, 1, 4, 10, 21, 28, 10, 11, 1, 1, 1, 20, 35, 36, 45, 12, 13, 1, 1, 5, 15, 56, 84, 55, 66, 14, 15, 1, 1, 1, 35, 70, 120, 165, 78, 91, 16, 17, 1, 1, 6, 21, 126, 210, 220, 286, 105, 120, 18, 19, 1, 1, 1, 56 (list; table; graph; refs; listen; history; internal format)
OFFSET

0,7

COMMENTS

Riordan array ((1+x-x^2)/(1-x^2)^2, x/(1-x^2)^2). Row sums are A108742. Diagonal sums are F(n+1). Corresponding diagonals triangle is A102426.

LINKS

D. Stutson, V. Kocic and G. Arora, A Few Identities involving Jacobsthal polynomials.

FORMULA

Number triangle T(n, k)=binomial(floor((n+k+1)/2)+k, floor((n+k)/2-k)

EXAMPLE

Rows begin

1;

1,1;

1,1,1;

2,3,1,1;

1,4,5,1,1;

3,6,6,7,1,1;

1,10,15,8,9,1,1;

CROSSREFS

Sequence in context: A180050 A202603 A140737 * A106178 A205104 A108714

Adjacent sequences:  A108753 A108754 A108755 * A108757 A108758 A108759

KEYWORD

easy,nonn,tabl

AUTHOR

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

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Last modified February 15 19:15 EST 2012. Contains 205852 sequences.