Numbers n such that phi(n) divides n+2.

Terms

a(0) =1a(1) =2a(2) =4a(3) =6a(4) =10a(5) =30a(6) =70a(7) =510a(8) =2590a(9) =131070a(10) =3359230a(11) =167247870a(12) =8589934590