Exponential generating function: 2*(1+3*x)/(1-2*x)^(7/2).

A000906

Exponential generating function: 2*(1+3*x)/(1-2*x)^(7/2).

Terms

    a(0) =2a(1) =20a(2) =210a(3) =2520a(4) =34650a(5) =540540a(6) =9459450a(7) =183783600a(8) =3928374450a(9) =91662070500

External references