First trisection of A028560.

Terms

a(0) =0a(1) =27a(2) =72a(3) =135a(4) =216a(5) =315a(6) =432a(7) =567a(8) =720a(9) =891a(10) =1080a(11) =1287a(12) =1512a(13) =1755a(14) =2016a(15) =2295a(16) =2592a(17) =2907a(18) =3240a(19) =3591a(20) =3960a(21) =4347a(22) =4752a(23) =5175a(24) =5616a(25) =6075a(26) =6552a(27) =7047a(28) =7560a(29) =8091