a(n) = phi(Lucas(n)).

Terms

a(0) =1a(1) =1a(2) =2a(3) =2a(4) =6a(5) =10a(6) =6a(7) =28a(8) =46a(9) =36a(10) =80a(11) =198a(12) =132a(13) =520a(14) =560a(15) =600a(16) =2206a(17) =3570a(18) =1908a(19) =9348a(20) =12960a(21) =11760a(22) =25704a(23) =63480a(24) =50692a(25) =150000a(26) =180960a(27) =208008a(28) =609084a(29) =1130304