a(n) = n!*(n+4)! / 4!.A010793a(n) = n!*(n+4)! / 4!.Terms a(0) =1a(1) =5a(2) =60a(3) =1260a(4) =40320a(5) =1814400a(6) =108864000a(7) =8382528000a(8) =804722688000External referencesoeis: A010793