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

Terms

a(0) =0a(1) =1a(2) =48a(3) =486a(4) =2560a(5) =9375a(6) =27216a(7) =67228a(8) =147456a(9) =295245a(10) =550000a(11) =966306a(12) =1617408a(13) =2599051a(14) =4033680a(15) =6075000a(16) =8912896a(17) =12778713a(18) =17950896a(19) =24760990a(20) =33600000a(21) =44925111a(22) =59266768a(23) =77236116a(24) =99532800a(25) =126953125a(26) =160398576a(27) =200884698