a(n) = (6*n)!/(5*n+1)!.A052795a(n) = (6*n)!/(5*n+1)!.Terms a(0) =1a(1) =1a(2) =12a(3) =306a(4) =12144a(5) =657720a(6) =45239040a(7) =3776965920a(8) =371090522880External referencesoeis: A052795