a(n) = n^5*(n+1)^2/2.

Terms

a(0) =0a(1) =2a(2) =144a(3) =1944a(4) =12800a(5) =56250a(6) =190512a(7) =537824a(8) =1327104a(9) =2952450a(10) =6050000a(11) =11595672a(12) =21026304a(13) =36386714a(14) =60505200a(15) =97200000a(16) =151519232a(17) =230016834a(18) =341067024a(19) =495219800a(20) =705600000a(21) =988352442a(22) =1363135664a(23) =1853666784