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Search: id:A090413
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A090413 A Chebyshev transform of 3^n. +0
1
1, 3, 8, 21, 56, 150, 400, 1065, 2840, 7578, 20208, 53874, 143664, 383148, 1021728, 2724465, 7265240, 19374450, 51665200, 137772246, 367392656, 979719348, 2612584928, 6966873546, 18578329456, 49542281220, 132112749920 (list; graph; listen)
OFFSET

0,2

FORMULA

G.f.: c(-x^2)/(1-3xc(-x^2)), c(x) g.f. of Catalan numbers A000108; a(n)=sum{k=0..n, (k+1)C(n, n/2-k/2)(-1)^(n/2-k/2)(1+(-1)^(n+k))3^k/(n+k+2)}.

CROSSREFS

Sequence in context: A088305 A072632 A001671 this_sequence A128105 A085560 A094374

Adjacent sequences: A090410 A090411 A090412 this_sequence A090414 A090415 A090416

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Dec 05 2003

page 1

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Last modified September 8 08:06 EDT 2008. Contains 143486 sequences.


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