a(n) = 2*n*binomial(n, 4).

Terms

a(0) =0a(1) =0a(2) =0a(3) =8a(4) =50a(5) =180a(6) =490a(7) =1120a(8) =2268a(9) =4200a(10) =7260a(11) =11880a(12) =18590a(13) =28028a(14) =40950a(15) =58240a(16) =80920a(17) =110160a(18) =147288a(19) =193800a(20) =251370a(21) =321860a(22) =407330a(23) =510048a(24) =632500a(25) =777400a(26) =947700a(27) =1146600a(28) =1377558a(29) =1644300