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Column 3 of triangle A128545; a(n) is the coefficient of q^(3n+9) in the central q-binomial coefficient [2n+6,n+3].
3

%I #3 Mar 30 2012 18:37:03

%S 1,5,18,58,155,383,867,1860,3782,7409,13989,25683,45905,80262,137453,

%T 231269,382689,624061,1003787,1594796,2504587,3892100,5988403,9129707,

%U 13798792,20688367,30781988,45473815,66723042,97276842,140959603

%N Column 3 of triangle A128545; a(n) is the coefficient of q^(3n+9) in the central q-binomial coefficient [2n+6,n+3].

%o (PARI) a(n)=polcoeff(prod(j=n+4,2*n+6,1-q^j)/prod(j=1,n+3,1-q^j),3*n+9,q)

%Y Cf. A128545; A128552, A128554.

%K nonn

%O 0,2

%A _Paul D. Hanna_, Mar 10 2007