a(n) = 5!*n*Stirling2(n-1, 5).

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =720a(7) =12600a(8) =134400a(9) =1134000a(10) =8341200a(11) =56133000a(12) =355291200a(13) =2151864000a(14) =12614281680a(15) =72135063000a(16) =404672486400