Position of n-th 2 in A031027.

Terms

a(0) =2a(1) =19a(2) =24a(3) =33a(4) =49a(5) =50a(6) =51a(7) =59a(8) =63a(9) =73a(10) =75a(11) =77a(12) =90a(13) =99a(14) =102a(15) =107a(16) =112a(17) =119a(18) =129a(19) =135a(20) =148a(21) =161a(22) =162a(23) =166a(24) =167a(25) =173a(26) =174a(27) =175a(28) =197a(29) =199