a(n) = (n+1)*binomial(n+1,5).

Terms

a(0) =5a(1) =36a(2) =147a(3) =448a(4) =1134a(5) =2520a(6) =5082a(7) =9504a(8) =16731a(9) =28028a(10) =45045a(11) =69888a(12) =105196a(13) =154224a(14) =220932a(15) =310080a(16) =427329a(17) =579348a(18) =773927a(19) =1020096a(20) =1328250a(21) =1710280a(22) =2179710a(23) =2751840a(24) =3443895a(25) =4275180a(26) =5267241a(27) =6444032a(28) =7832088a(29) =9460704