Position of n-th 3 in A030998.

Terms

a(0) =3a(1) =14a(2) =28a(3) =35a(4) =37a(5) =39a(6) =41a(7) =42a(8) =43a(9) =45a(10) =47a(11) =56a(12) =70a(13) =84a(14) =102a(15) =123a(16) =144a(17) =155a(18) =158a(19) =161a(20) =164a(21) =165a(22) =167a(23) =170a(24) =173a(25) =186a(26) =207a(27) =228a(28) =249a(29) =270