Position of n-th 1 in A031253.

Terms

a(0) =1a(1) =3a(2) =5a(3) =7a(4) =10a(5) =20a(6) =23a(7) =26a(8) =29a(9) =32a(10) =33a(11) =34a(12) =35a(13) =36a(14) =38a(15) =41a(16) =44a(17) =47a(18) =49a(19) =50a(20) =53a(21) =56a(22) =59a(23) =64a(24) =69a(25) =72a(26) =75a(27) =79a(28) =94a(29) =108