a(n) = 2^n*(Gamma(n+1/2)/Gamma(1/2) + (n-1)!).

A123332

a(n) = 2^n*(Gamma(n+1/2)/Gamma(1/2) + (n-1)!).

Terms

    a(0) =3a(1) =7a(2) =31a(3) =201a(4) =1713a(5) =18075a(6) =227295a(7) =3317265a(8) =55103265a(9) =1026318195a(10) =21181092975a(11) =479733356025

External references