Position of n-th 4 in A031057.

Terms

a(0) =29a(1) =31a(2) =33a(3) =35a(4) =110a(5) =113a(6) =116a(7) =119a(8) =206a(9) =209a(10) =212a(11) =215a(12) =302a(13) =305a(14) =308a(15) =311a(16) =349a(17) =352a(18) =355a(19) =358a(20) =361a(21) =364a(22) =367a(23) =370a(24) =373a(25) =376a(26) =379a(27) =382a(28) =385a(29) =388