Product of first n odd numbers plus product of first n even numbers: (2n-1)!! + (2n)!!, where k!! = A006882(k).

A232617

Product of first n odd numbers plus product of first n even numbers: (2n-1)!! + (2n)!!, where k!! = A006882(k).

Terms

    a(0) =3a(1) =11a(2) =63a(3) =489a(4) =4785a(5) =56475a(6) =780255a(7) =12348945a(8) =220253985a(9) =4370620275a(10) =95498916975

External references