Numbers n such that sigma(x) = n has no solution.

Terms

a(0) =2a(1) =5a(2) =9a(3) =10a(4) =11a(5) =16a(6) =17a(7) =19a(8) =21a(9) =22a(10) =23a(11) =25a(12) =26a(13) =27a(14) =29a(15) =33a(16) =34a(17) =35a(18) =37a(19) =41a(20) =43a(21) =45a(22) =46a(23) =47a(24) =49a(25) =50a(26) =51a(27) =52a(28) =53a(29) =55