a(n) = (2*n + 3)!!/3 = A001147(n+2)/3.
A051577
a(n) = (2*n + 3)!!/3 = A001147(n+2)/3.
Terms
- a(0) =1a(1) =5a(2) =35a(3) =315a(4) =3465a(5) =45045a(6) =675675a(7) =11486475a(8) =218243025a(9) =4583103525a(10) =105411381075
External references
- oeis: A051577