a(n) = (8*n+6)^5.

Terms

a(0) =7776a(1) =537824a(2) =5153632a(3) =24300000a(4) =79235168a(5) =205962976a(6) =459165024a(7) =916132832a(8) =1680700000a(9) =2887174368a(10) =4704270176a(11) =7339040224a(12) =11040808032a(13) =16105100000a(14) =22877577568a(15) =31757969376a(16) =43204003424a(17) =57735339232a(18) =75937500000a(19) =98465804768a(20) =126049300576a(21) =159494694624a(22) =199690286432