Numbers m such that b^sigma(m) == b^phi(m) == b^numdiv(m) == b^m (mod m) for every integer b.

Terms

a(0) =1a(1) =2a(2) =6a(3) =12a(4) =24a(5) =60a(6) =120a(7) =126a(8) =240a(9) =420a(10) =480a(11) =504a(12) =672a(13) =780a(14) =1248a(15) =1260a(16) =2340a(17) =2520a(18) =3360a(19) =4680a(20) =5040a(21) =5460a(22) =6240a(23) =6552a(24) =8160a(25) =8736a(26) =9360a(27) =10080a(28) =11424a(29) =16380