a(1)=1, a(2)=2. a(n) is the a(n-1)th integer from among those positive integers coprime to a(n-2).

Terms

a(0) =1a(1) =2a(2) =2a(3) =3a(4) =5a(5) =7a(6) =8a(7) =9a(8) =17a(9) =25a(10) =26a(11) =32a(12) =69a(13) =137a(14) =214a(15) =215a(16) =433a(17) =553a(18) =554a(19) =654a(20) =1311a(21) =3967a(22) =6565a(23) =6566a(24) =8979a(25) =21267a(26) =33151a(27) =53216a(28) =53217a(29) =106497