Numbers k such that phi(k) divides k + 3.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =9a(5) =21a(6) =45a(7) =285a(8) =765a(9) =27645a(10) =196605a(11) =41067645a(12) =72787965a(13) =250871805a(14) =4295098365a(15) =12884901885