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A107238 A Chebyshev transform of number triangle A107230. 0
1, 1, 1, 0, 2, 1, 0, 3, 3, 1, 0, 4, 8, 4, 1, 0, 5, 15, 15, 5, 1, 0, 6, 27, 36, 24, 6, 1, 0, 7, 42, 84, 70, 35, 7, 1, 0, 8, 64, 160, 200, 120, 48, 8, 1, 0, 9, 90, 300, 450, 405, 189, 63, 9, 1, 0, 10, 125, 500, 1000, 1050, 735, 280, 80, 10, 1, 0, 11, 165, 825, 1925, 2695, 2156, 1232, 396 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,5

COMMENTS

Product of the number triangle A107230 by the Riordan array ((1-x^2)/(1+x^2),x/(1+x^2)). First column if C(1,n), second column is n (A001477), third column is essentially A034828.

LINKS

Table of n, a(n) for n=0..74.

FORMULA

Number triangle T(n, k)=sum{j=0..floor(n/2), (n/(n-j))(-1)^j*C(n-j, j)*A107230(n-2j, k)} (with T(0, n)=0^n).

EXAMPLE

Triangle begins

1;

1,1;

0,2,1;

0,3,3,1;

0,4,8,4,1;

0,5,15,15,5,1;

CROSSREFS

Sequence in context: A206735 A089000 A253829 * A258170 A055830 A293109

Adjacent sequences:  A107235 A107236 A107237 * A107239 A107240 A107241

KEYWORD

easy,nonn,tabl

AUTHOR

Paul Barry, May 14 2005

STATUS

approved

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Last modified October 19 04:40 EDT 2019. Contains 328211 sequences. (Running on oeis4.)