a(n) = n!*(n+1)!*(n+2)!.A176037a(n) = n!*(n+1)!*(n+2)!.Terms a(0) =2a(1) =12a(2) =288a(3) =17280a(4) =2073600a(5) =435456000a(6) =146313216000External referencesoeis: A176037