Numbers that do not divide 2^k + 1 for any k>0.

Terms

a(0) =2a(1) =4a(2) =6a(3) =7a(4) =8a(5) =10a(6) =12a(7) =14a(8) =15a(9) =16a(10) =18a(11) =20a(12) =21a(13) =22a(14) =23a(15) =24a(16) =26a(17) =28a(18) =30a(19) =31a(20) =32a(21) =34a(22) =35a(23) =36a(24) =38a(25) =39a(26) =40a(27) =42a(28) =44a(29) =45