Numbers k such that phi(x) = k has exactly 2 solutions.

Terms

a(0) =1a(1) =10a(2) =22a(3) =28a(4) =30a(5) =46a(6) =52a(7) =54a(8) =58a(9) =66a(10) =70a(11) =78a(12) =82a(13) =102a(14) =106a(15) =110a(16) =126a(17) =130a(18) =136a(19) =138a(20) =148a(21) =150a(22) =166a(23) =172a(24) =178a(25) =190a(26) =196a(27) =198a(28) =210a(29) =222