a(n) = n*phi(n*phi(n)).

Terms

a(0) =1a(1) =2a(2) =6a(3) =16a(4) =40a(5) =24a(6) =84a(7) =128a(8) =162a(9) =160a(10) =440a(11) =192a(12) =624a(13) =336a(14) =480a(15) =1024a(16) =2176a(17) =648a(18) =2052a(19) =1280a(20) =1512a(21) =1760a(22) =5060a(23) =1536a(24) =5000a(25) =2496a(26) =4374a(27) =2688a(28) =9744a(29) =1920