%I #6 Mar 31 2012 14:41:37

%S 1,9,133,2283,41589,782149,15007831,291987327,5738781717,113670432141,

%T 2265365597553,45371770152927,912463490703879,18413786266130979,

%U 372689501160357787,7562267679664012693,153785739808245476757

%N Trinomial transform of central binomial coefficients (A000984).

%F a(n) = Sum[ Binomial[2k, k] Trinomial[n, k], {k, 0, 2n} ] where Trinomial[n, k] = trinomial coefficients (A027907)

%F a(n)=sum{k=0..n, sum{j=0..n, C(n, j)C(j, k)C(2(j+k), j+k)}}; - _Paul Barry_, Feb 15 2005

%K easy,nonn

%O 0,2

%A _Emanuele Munarini_, May 21 2003