a(n) = (4*n)^5.

Terms

a(0) =0a(1) =1024a(2) =32768a(3) =248832a(4) =1048576a(5) =3200000a(6) =7962624a(7) =17210368a(8) =33554432a(9) =60466176a(10) =102400000a(11) =164916224a(12) =254803968a(13) =380204032a(14) =550731776a(15) =777600000a(16) =1073741824a(17) =1453933568a(18) =1934917632a(19) =2535525376a(20) =3276800000a(21) =4182119424a(22) =5277319168a(23) =6590815232a(24) =8153726976a(25) =10000000000