a(n) = 3*2^(2*n)*(3*n)!/((2*n)!*n!).
A006587
a(n) = 3*2^(2*n)*(3*n)!/((2*n)!*n!).
Terms
- a(0) =3a(1) =36a(2) =720a(3) =16128a(4) =380160a(5) =9225216a(6) =228114432a(7) =5715394560a(8) =144599482368
External references
- oeis: A006587
A006587
a(n) = 3*2^(2*n)*(3*n)!/((2*n)!*n!).