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A014330 Exponential convolution of Catalan numbers with themselves. +0
1
1, 2, 6, 22, 92, 424, 2108, 11134, 61748, 356296, 2123720, 13002840, 81417520, 519550880, 3369559864, 22161337742, 147544048324, 992923683912, 6746101933304, 46226667046360, 319199694771696 (list; graph; listen)
OFFSET

0,2

FORMULA

E.g.f.: exp(4*x)*(BesselI(0, 2*x)-BesselI(1, 2*x))^2. a(n) = Sum_{k=0..n} binomial(n, k)*binomial(2*k, k)/(k+1)*binomial(2*n-2*k, n-k)/(n-k+1) = 4^n*Sum_{k=0..n} (-4)^(-k)*binomial(n, k)*binomial(k, floor(k/2))*binomial(k+1, floor((k+1)/2)) = binomial(2*n, n)/(n+1)*hypergeom([ -n-1, -n, 1/2], [2, 1/2-n], -1). - Vladeta Jovovic (vladeta(AT)eunet.rs), Jan 01 2004

(n + 1)*(n + 2)*a(n) = 4*(3*n^2 + n - 1)*a(n - 1) - 32*(n - 1)^2*a(n - 2). - Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 15 2004

a(n) = Sum_{k,0<=k<=n}binomial(n,k)*A000108(k)*A000108(n-k) . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Aug 23 2006

CROSSREFS

Cf. A000108.

Sequence in context: A001181 A130579 A107945 this_sequence A124294 A124295 A074664

Adjacent sequences: A014327 A014328 A014329 this_sequence A014331 A014332 A014333

KEYWORD

nonn

AUTHOR

N. J. A. Sloane (njas(AT)research.att.com).

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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