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A128594 Column 2 of triangle A128592; a(n) = coefficient of q^(2n+6) in the q-analog of the odd double factorials (2n+5)!! for n>=0. 3

%I

%S 1,12,97,696,4784,32230,214978,1426566,9441417,62405645,412278981,

%T 2723566163,17996243101,118957645301,786700165122,5205396517853,

%U 34461624895701,228274455988134,1512920531980961,10032446308837778

%N Column 2 of triangle A128592; a(n) = coefficient of q^(2n+6) in the q-analog of the odd double factorials (2n+5)!! for n>=0.

%F a(n) = [q^(2n+6)] Product_{j=1..n+3} (1-q^(2j-1))/(1-q) for n>=0.

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

%Y Cf. A128592; A128080; A001147 ((2n-1)!!); A128593 (column 1), A128595 (row sums).

%K nonn

%O 0,2

%A _Paul D. Hanna_, Mar 12 2007

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Last modified June 25 03:30 EDT 2021. Contains 345449 sequences. (Running on oeis4.)