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

Terms

a(0) =0a(1) =256a(2) =4096a(3) =20736a(4) =65536a(5) =160000a(6) =331776a(7) =614656a(8) =1048576a(9) =1679616a(10) =2560000a(11) =3748096a(12) =5308416a(13) =7311616a(14) =9834496a(15) =12960000a(16) =16777216a(17) =21381376a(18) =26873856a(19) =33362176a(20) =40960000a(21) =49787136a(22) =59969536a(23) =71639296a(24) =84934656a(25) =100000000a(26) =116985856a(27) =136048896a(28) =157351936a(29) =181063936