Numbers n such that phi(n)+phi(n+1)=n+1.

Terms

a(0) =1a(1) =2a(2) =3a(3) =5a(4) =9a(5) =15a(6) =21a(7) =35a(8) =39a(9) =45a(10) =75a(11) =99a(12) =135a(13) =231a(14) =255a(15) =363a(16) =483a(17) =765a(18) =855a(19) =1295a(20) =1599a(21) =2015a(22) =2115a(23) =4335a(24) =6783a(25) =9999a(26) =14399a(27) =16095a(28) =16599a(29) =18495