Position of n-th 2 in A031312.

Terms

a(0) =16a(1) =18a(2) =20a(3) =22a(4) =24a(5) =127a(6) =130a(7) =133a(8) =136a(9) =139a(10) =246a(11) =249a(12) =252a(13) =255a(14) =258a(15) =261a(16) =264a(17) =267a(18) =270a(19) =273a(20) =276a(21) =277a(22) =279a(23) =280a(24) =282a(25) =283a(26) =285a(27) =286a(28) =288a(29) =289