Numbers k such that gcd(phi(k), k-1) = number of divisors of (k-1).

Terms

a(0) =2a(1) =3a(2) =105a(3) =133a(4) =153a(5) =185a(6) =345a(7) =377a(8) =425a(9) =585a(10) =637a(11) =665a(12) =777a(13) =805a(14) =825a(15) =873a(16) =897a(17) =905a(18) =949a(19) =1017a(20) =1090a(21) =1113a(22) =1209a(23) =1225a(24) =1261a(25) =1305a(26) =1309a(27) =1385a(28) =1449a(29) =1525