Numbers k such that phi(k) = phi(k+2) - phi(k+1).

Terms

a(0) =1a(1) =3a(2) =5a(3) =9a(4) =15a(5) =21a(6) =35a(7) =39a(8) =45a(9) =99a(10) =135a(11) =231a(12) =255a(13) =855a(14) =1035a(15) =1295a(16) =1539a(17) =1599a(18) =2015a(19) =4335a(20) =6525a(21) =9177a(22) =14399a(23) =16095a(24) =30495a(25) =55385a(26) =61131a(27) =62799a(28) =65535a(29) =72579