a(n) = (6n)!n!/((3n)!(2n)!^2).A061162a(n) = (6n)!n!/((3n)!(2n)!^2).Terms a(0) =1a(1) =30a(2) =2310a(3) =204204a(4) =19122246a(5) =1848483780a(6) =182327718300External referencesoeis: A061162