a(n) = gcd(sigma(n), phi(n)).

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =2a(5) =2a(6) =2a(7) =1a(8) =1a(9) =2a(10) =2a(11) =4a(12) =2a(13) =6a(14) =8a(15) =1a(16) =2a(17) =3a(18) =2a(19) =2a(20) =4a(21) =2a(22) =2a(23) =4a(24) =1a(25) =6a(26) =2a(27) =4a(28) =2a(29) =8