a(n) = smallest k >= n such that k | (2^k + n).

Terms

a(0) =1a(1) =2a(2) =5a(3) =4a(4) =7a(5) =10a(6) =15a(7) =8a(8) =11a(9) =14a(10) =13a(11) =28a(12) =21a(13) =78a(14) =17a(15) =16a(16) =19a(17) =22a(18) =49a(19) =42a(20) =23a(21) =26a(22) =1577a(23) =40a(24) =33a(25) =30a(26) =29a(27) =44a(28) =31a(29) =34