a(n) = (2*n+4)!!/4!!, related to A000165 (even double factorials).
A051578
a(n) = (2*n+4)!!/4!!, related to A000165 (even double factorials).
Terms
- a(0) =1a(1) =6a(2) =48a(3) =480a(4) =5760a(5) =80640a(6) =1290240a(7) =23224320a(8) =464486400a(9) =10218700800a(10) =245248819200
External references
- oeis: A051578