a(n) = (4n)^6.

Terms

a(0) =0a(1) =4096a(2) =262144a(3) =2985984a(4) =16777216a(5) =64000000a(6) =191102976a(7) =481890304a(8) =1073741824a(9) =2176782336a(10) =4096000000a(11) =7256313856a(12) =12230590464a(13) =19770609664a(14) =30840979456a(15) =46656000000a(16) =68719476736a(17) =98867482624