a(0) = 1; for n > 0, a(n) = n!*4^n/2.

A051711

a(0) = 1; for n > 0, a(n) = n!*4^n/2.

Terms

    a(0) =1a(1) =2a(2) =16a(3) =192a(4) =3072a(5) =61440a(6) =1474560a(7) =41287680a(8) =1321205760a(9) =47563407360

External references