Quadruple factorial numbers: a(n) = (2n)!/n!.
A001813
Quadruple factorial numbers: a(n) = (2n)!/n!.
Terms
- a(0) =1a(1) =2a(2) =12a(3) =120a(4) =1680a(5) =30240a(6) =665280a(7) =17297280a(8) =518918400a(9) =17643225600a(10) =670442572800
External references
- oeis: A001813