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A102879 A Chebyshev transform of the first kind of the central binomial numbers. 1
1, 2, 4, 14, 48, 162, 556, 1934, 6784, 23954, 85044, 303294, 1085712, 3898962, 14040156, 50678814, 183309312, 664263714, 2411050084, 8764098158, 31899231088, 116244082178, 424064770188, 1548543412398, 5659898710912 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Image of 1/sqrt(1-4x) under the mapping g(x)->((1-x^2)/(1+x^2))g(x/(1+x^2)).

FORMULA

G.f.: (1-x^2)/sqrt(1-4x+2x^2-4x^3+x^4); a(n)=n*sum{k=0..floor(n/2), C(n-k, k)(-1)^k*C(2(n-2k), n-2k)/(n-k)}.

CROSSREFS

Cf. A101500, A102880.

Sequence in context: A054936 A006443 A152103 * A032312 A032222 A092665

Adjacent sequences:  A102876 A102877 A102878 * A102880 A102881 A102882

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Jan 15 2005

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Last modified February 17 11:46 EST 2012. Contains 206011 sequences.