a(n) = 2*(3*n)!/(n!*(n+1)!^2).
A361028
a(n) = 2*(3*n)!/(n!*(n+1)!^2).
Terms
- a(0) =2a(1) =3a(2) =20a(3) =210a(4) =2772a(5) =42042a(6) =700128a(7) =12471030a(8) =233716340a(9) =4557468630a(10) =91752013080
External references
- oeis: A361028
A361028
a(n) = 2*(3*n)!/(n!*(n+1)!^2).